Jan 31, 2020 · How does fan clutch solenoids work?When the engine is cool or even at normal operating temperature, the fan clutch partially disengages the engine's mechanically driven radiator cooling fan, generally located at the front of the water pump and driven by a belt and pulley connected to the engine's crankshaft. Dual function Normally Open / Close Thermal Switch for Fan Clutch. Kenworth. Core Charge: 0. Kit includes valve, wire harness with Weather-Pack sealed connectors, exhaust shield, in-line fitter and butt connectors. I would try changing the solenoid first (that is assuming your trucks air system is set up the same as ours. Same day worldwide shipping. 406 Inch * 3. 077 Inch * Normally Closed * 3 Way * 12 Volt * 2 Pin * Sold Individually * Warranty On Solenoid Valve Fan Clutches Against Defects In Workmanship & Material From Date Of Purchase *** High Quality Aftermarket Replacement Part (Not OEM)*** ** This Item Ships Direct From The Manufacturer And Will Arrive In A Separate Package And Possibly A Jul 11, 2015 · No power is applied to the solenoid when it engages the fan clutch. Fan Solenoid for trucks that utilize a 2 speed fan clutch. Fairly easy to change. Order Now 8037061 High Temperature Dual Thermal Switch 220 degrees. Source One Parts Center selection of genuine OEM Kenworth® Truck Parts | Engine Cooling Fan | Fan Clutch Solenoid Valve parts for Trucks, Buses, and more. This is located behind the upper radiator hose/thermostat adapter. 14 Fan speed when fan clutch is fully engaged = 1800RPM • HP Draw = 65 *Data based on engine speed of 1800 RPM. 1. Velvac® Universal Solenoid Kit replaces existing solenoids found on Kysor, Bendix and Horton fan clutches. I need to know the correct pins on the engine ECM to test. K. Its miniature size allows for easy installation in tight spaces, while its solenoid Ensure your semi is Ready for the Road Ahead™ with efficient engine cooling, with the Horton 12V NO / NC 3-Way Fan Clutch Solenoid Valve Kit. Product Overview. What other items might share that power circuit maybe while running, egr, turbo actuator, lambda, coolant pump speed ect. If not it could be the engine ECM or wiring between the ECM and fan solenoid. Same day Worldwide Shipping. Fan Clutch Solenoid Valves - H/D Truck. Freightliner. Oct 9, 2018 · Rebuilding a Horton fan clutch that’s on a Cat C 12 engine that’s in a 2000 Kenworth T800. Menu FinditParts. Jan 29, 2009 · Air line in, out and a couple of wires. Thanks to its electrically-energized design, this replacement valve is able to control the flow of electricity to the fan, powering the device as needed to decrease the temperature of the engine. While using eddy current, the fan clutch turns the fan at a lower speed, which reduces operating noise, increases available horsepower for auxiliary systems and minimizes radiator abrasion from dust and debris. have to drain the coolant about 3 gal to remove this with out a big mess. Kenworth t800 Fan Clutch on HeavyTruckParts. $812. I was wondering if anybody had any ideas. This part is essential in applications May 29, 2015 · The ECM sends out 12 volts from pin 11 to turn the fan off. Availability KENWORTH: G90-6047: OTHER: G90-6047, 993379H0R: PETERBILT: G90-6047: Vehicle Fitment Feb 17, 2016 · Posted 2/17/2016 22:09 (#5119332 - in reply to #5119091) Subject: RE: t600 kenworth fan. 12 add to cart. This item is NOT eligible for returns or cancellations. 50 Beautiful Kenworth Engine Fan Wiring Diagram- Wiring a ceiling follower is surprisingly simple. Fits 2001-2023+ Kenworth T680, T800, T880, W900 trucks and more with Cummins ISX / X15 engines. going to it. T2000 Apr 8, 2024 · Solenoid valve clutch fan kenworth g90 international air truck atpKenworth engine fan wiring diagram : solved wiring diagram for radiator Blower resistor wiring kenworth voltKenworth starter relay wiring diagram. c sensor and fan switch solenoid. Wheelco Quick Clips | Compatibility: The A06-26631-000 | FR-ENGN706 Fan Clutch Solenoid fits various truck brands, including Volvo, Freightliner, Peterbilt, Kenworth, and Mack. The Horton clutch seems to be in good working order and will release with air pressure. Net. Nov 20, 2017 · How to replace a fan clutch on a Paccar engine and what is inside it that will cause it to fail. About: This part is a precise electromechanical device crucial for managing fluid flow within systems. Feb 23, 2014 · There are vanes inside the fan drive which the fan speed sensor/solenoid reads (Hall Effect like a crank sensor) It sends a signal to the ECM and engages the fan accordingly for optimal cooling speed. Line: Traction. About: This kit includes all necessary components for solenoid valve maintenance and repair, ensuring long-term functionality. I have a 2018 Kenworth T680 with a X15 Cummins. Install a jumper wire between the terminals of the N. 90. Sep 22, 2021 · A minimum of 90 psi is required for the fan clutch to correctly engage (S & HT/S) and/or disengage (DriveMaster, DMA & DMA-2S) the Horton fan clutch. Keep hands and tools clear of the fan blades. at Raney's? 888-888-7990. VIN #: 1xkydk9xxgj116091. I can send some diagrams if you can get the last 6 of the VIN. I started the engine 2. Vehicle Information. Price. 50 inches. You need to find out whether you have an electronic problem, such as a bad solenoid, or an air supply problem. I replaced the temperature sensor and teh solenoid was leaking so i bought a new one. Unit of Measurement: Each. $69. Also check the manual on off fan switch on the dash. $42. High Quality Solenoid Valve Fan Clutch * Length- 4. OE-Genuine Replacement for Freightliner #A0626631000 with Detroit Diesel Engine. Its robust design ensures reliability across a wide range of operating conditions Specifications. Kenworth® 993366H0R | VALVE. Upgraded Lining For Extended Life. When the ECM wants the fan on, it will remove the 12 volts from pin 11. Most often the problem with C15 engines is the fan is on all the time. The fan clutch is responsible for controlling the operation of the cooling fans. Jul 14, 2021 · The most likely cause of this issue is an a/c fan override switch or wiring to the switch. if nothing else. Goodysnap, Nov 11, 2020. Dearfield Co. Conversely, applying air disengages it. There is several of these normally closed switches on the a/c and temp sensor and then there is the solenoid itself the one that gives air pressure to the fan clutch. Steps 1-2 1. Specials. 99. The choices are: ON/OFF - Most ECM controlled fans are classified as ON/OFF fans. OEM P/N F17-1019M03 , Horton brand P/N P98A7239. I have good air pressure. 993379H0R KIT,SOLENOID VALVE is an OEM part from Kenworth®, VMRS Code: 042-003-024, OEM Part Number: 993379H0R-412. Nov 4, 2023 · Valve-solenoid normally open 5022-106Hor993293 by horton fans valve, solenoid, fan clutch, 3-way, no-nc Solenoid valve a06 air freightliner kenworth advance truck parts clutch fan g90 international currency2014 peterbilt 389 fan clutch. Create Estimate. OEM #: F17-6018M13. 2015 kenworth t370 wiring diagramHow to look up wiring diagrams for kenworth Kenworth w900 t800 radiator radiowiring blower fuse wire. The solenoid is normally powered up to pass air to the clutch to keep it from engaging. While the engine is running the A/C isn't blowing cold air (the fan is still on) 3. Jan 17, 2008 · Fan clutches fail to the on positon and it requires air (from the solenoid) to turn the fan OFF. Part Info. 63. SAD. OEM #: F17-1046-001. Mounting Diameter: 3. Qty: Add to Cart. Install the Horton EC450 TM Fan Clutch on the engine. AIR. Fan clutch off of an MX11 engine pulled from a 2016 Kenworth T680 run for only 20K miles, non-wrecked. Try running a separate power or grounds to the solenoid to see if you can manually bypass power to engage and disengage your fan at tthe solenoid. the one you want to replace will have HORTION on the side of the part. With the engine temperature below the Thermal Switch setting, turn on the ignition and build up air pressure. If it does this then you will know that the problem is either the ecm/solonoid, if it doesn't then it's the fan cluch. $22. The fan clutch has minor corrosion and rust. 50 Beautiful Kenworth Engine Fan Wiring Diagram. Video library. Our revamped online catalog features simple part number and VIN lookup, easy-to-find repair and replacement options and a more user-friendly navigation. Dec 12, 2019 · LongHaul Larry P. Dealer had the pressure switch in stock but I can't find it anywhere on the engine to replace it. As taking into account any electrical wiring, make determined all wire friends are made securely bearing in mind the Jun 23, 2010 · Jun 23, 2010. This problem is occurring when the solenoid is powered down. You will have to trace the wires --------It seems to me the fan control solenoid should be on the firewall by the hvac system or in that area. Jul 24, 2014 · Plenty of things can cause this from a faulty fan clutch to a bad solenoid, switches, or wiring. Solenoid State: Normally Closed NOTE: For use with a 2 speed fan hub ONLY Kenworth . Closed or jumpered should change you input signal to Insite (ECM). My fan is designed to stay on from 500 rpms and up, when the truck hits the clutch engagement temperature the clutch goes to high speed. O. Anyways, 1. Skip to the beginning of the images gallery. Watch: It's easy to overlook, but a truck's fan clutch can make a world of difference. 2016 KENWORTH T680 Fan Clutch. Committed to service, reliability, innovation and the environment, Horton is a premium provider Horton f01 justanswer solenoid agus kenworth. Valve-Solenoid-Clutch Fan C4R920DC14R8. It is designed for reliability and efficient performance, responding accurately to electrical signals. Feb 21, 2023 · i have a 2008 Kenworth T2000 with a cummins ISX in it the fan clutch dose not turn off when we turn the key of the fan clutch solenoid disengages it and the fan spins freely when we start the truck it … read more Jul 24, 2014 · I've got a 2013 kenworth t660, mine does the same. Mar 22, 2019 · The ECM controls the low side (ground) of the engine fan relay to cycle the fan as needed. I replaced Hi pressure a. 0. I can disconnect airline from solenoid to fan clutch and turn key on. . Aug 24, 2013 · Because the temp sensor for the ecm would leave a code if it was disconnected or if the ecm sees higher than normal temp on the coolant. Ensure your commercial vehicle's cooling system operates efficiently and reliably. The air solenoid on the firewall has no power and the manual rocker swich has power only on one side "the yellow/orange wire". 53079 Lhl820@yahoo. Sep 10, 2019 · Replacing fan clutch on paccar mx13. You would have to verify with DDDL, but most I seen with DDEC fan controls turn fan on around 210 F and remains on for 180 seconds. If the fan is released with the key on this is most likely the issue. Its not that expensive but on my truck an sob to get to. 8073906 OIL Temperature Sensor for Mack Volvo. Why Shop. Inspect the fan belt for signs of wear and tear, and check for any loose connections. If an air line is kinked the electronics can work just fine but the fan will be on. May 27, 2020 · For this video, we used an electric over air fan clutch. Skip to the end of the images gallery. VIN #: 1XKZDK9X6LJ407749. Casting#: 601196. $244. Learn More. 0. 2020 KENWORTH T880 Fan Clutch. Large Selection of Solenoid Valves at Advance Truck Parts. It is a block and bleed function where it blocks the supply pressure and then bleeds the output going to the clutch to cause it Nov 16, 2020 · engine fan stuck in the engaged position. My fan clutch will not engage automatically but will engage when you press the manual switch the truck is a Kenworth WL 900 2,006 model It has a C 15 and it is air operated fan clutch Mechanic's Assistant: Sometimes things that you think will be really complicated end up being easy to fix. Valve-Solenoid-Clutch Fan. Check for any broken parts, and inspect the fan clutch for signs of wear and tear. Often period it is no more complicated than the wiring of a lively fixture. With a block diagram, that circuit would show the items involved and maybe the origin of the splitting -off of that power to the individual items, again . Oct 24, 2019 · Fan switch should be normally open. The pully spins freely. They get you in and out fast and always go a great job. About: Featuring advanced electromechanical technology, this solenoid valve ensures precise control of fluid flow in complex systems. Kenworth G90-6047 Valve-Solenoid Normally Closed Order now for same-day shipping on eligible purchases from FinditParts. The first thing we need to figure out is if the fan takes 12 volts to engage or 12 volts to disengage. I tried shutting down the engine and restarting, didn't help. Easily find what you need from 2,648,799 parts available. Oct 31, 2021 · why engine Fan is not turning up on Semi Truck?how to diagnose fan clutch Problem on Freightliber?what happens if fan clutch go bad?can I drive with Bad fan Mar 8, 2019 · 0. Think it's the Solenoid valve, or is there a preesure switch. Check for air at the clutch or soleniod. C. I unplugged air line thats going toward fan clutch and the air is not blowing from the solenoid (out toward fan clutch) 3. Just unhook the airline running into the fan and use shop air to see if the fan will pop out and free spin. 05' Pete 379 with a Cat ACERT: The last few day's the engine fan has been staying on 90 % of the time. Part# C4R920DC14R8 OLD# -. Please note: this is an aftermarket part, the use of other Specifications. My local dealer in Carlisle Pa is great. requiring a rebuild or new clutch. Ships Today. Found the source to be a fitting on a component that is above the top of the trans bell housing and looks to be mounted to the bottom of the floor of the cab. Fan Pilot Diameter: 2. Mount the Solenoid Valve on either the vehicle Feb 2, 2012 · 2000 Kenworth w900l Cummins isx. Removing air from clutch engages fan. #fanclutch #enginefan #fanhubHello, and welcome once again to another DIY SEMI project. About: This solenoid valve stands out for its precision in controlling fluid dynamics within various systems, responding effectively to electrical signals. A06-266351-000 with 12 months Warranty. The fan clutch has been visually inspected and is in good working condition. Horton brand P/N F17-6018M13. A/C high pressure switch is only a couple months old. com FREE DELIVERY possible on eligible purchases Peterbilt Kenworth Fan Clutch Valve Solenoid PN-P55D-541 PNP55D541 - Raney's Truck Parts. Part Number: 1731101. I checked A/C compressor and its working fine, and the lines are getting cold. QTY. Which KW dealer were you at. The casting number is 601196. It does. Mar 26, 2013 · Looking for help as o what the cause of the fan clutch working backwards. Any ideas. Part is in good used condition, see pictures. 97. The coolant gauge reading and high temp warning light are signaled from Kenworth supplied sending units, not the engine ECM. Kenworth EC450TM Fan Clutch NOTE Do not loosen the P-clamp attaching the wiring harness to the metal tab on the Fan Clutch. When engine is off I hear no air leaks in engine compartment. Air Operated. ATP Thermal Fan Solenoid Switch 210 Deg 8037228 8037228P. Price $136. That would be about a $100 fix. 375 Inch Length * 12 Volt * Sold Individually * Warranty On Fan Clutch Solenoid Valve Against Defects In Workmanship & Material From Date Of Purchase ***High Quality Aftermarket Replacement Part (Not OEM)*** 1689785C91 5030-310B 5030310B Dec 29, 2012 · Posted August 9, 2019. Item:KM 99317. Designed for ease of use, it's tailored for quick replacement, minimizing downtime and maintaining optimal flow control in automated systems. Ditto on baha description. VALVE,SOLENOID - FAN CLUTCH SOLENOID VALVE $74. Add To Cart. Good, used fan clutch from a Cummins N14 engine. Apr 24, 2011 · In my case its a "shutter" valve, a thermostatically controlled air valve that controls the pressure to the fan clutch. 032194VEL VALVE - 4 WAY MINI SOLENOID is an OEM part from Kenworth®, Manufacturer Part Number: 032194, OEM Part Number: 032194VEL-475M, VMRS Code: 042-003-024. Replaces K22, K26, K30 and K32 style rear air fan clutches. Fan clutch slipping. I checked the power connector thats connecting with solenoid power and there is power. Mine has a bank of 5 solenoids under the truck. Turns out you have options on fans when ordering, I have a 2 speed fan and I'll bet you have one too. A fan clutch is a thermostatic engine cooling fan that can freewheel at low temperatures when cooling is not needed, allowing the engine to warm up faster, relieving the unnecessary load on the engine. lhlprint. Trace back the air line out of the clutch. 25 with. Horton fan clutch wiring diagramHorton works roadtrains bolts Horton 7000 wiring diagramHorton wiring. disconnect it and see if it changes it, if it doesnt the next thing you can look at is the older Oct 17, 2023 · Cummins n14 plus in a 1995 t600 kenworth need wiring diagramsEngine headlight mack schematics v70 kenworth bluebird freightliner mercruiser detoxicrecenze baseboard heater mr688s turn retrofitting bookingritzcarlton s70 refer 122s 240v [diagram] kenworth engine fan solenoid wiring diagram[diagram] kenworth t800 heater fan wiring diagram. Login Close search (888) 312-8812 Cart Welcome to JA! Yes this sounds like the fan temp sensor. The Fan Clutch can engage without warning. Universal kit replaces existing solenoids found on Kysor, Bendix and Horton fan clutches. The solenoid valve is a three-way valve with two inlet/exhaust ports and one outlet port. You would also need to change out your solenoid valve with this conversion because the Horton® HT/S style fan clutches are –air-to-engage” and GoldTop fan Apr 13, 2008 · If you unplug solenoid, fan should default to on position. Are you able to find that out for me? My number on ECM is 79959251 You are using Horton's legacy online catalog, which will be permanently disabled on a date TBD. 56 inches. Buying Guides. Jan 11, 2009 · You can check the fan clutch hub yourself if you have shop air availible. Order Now Volvo Truck 20807261 Fan Solenoid valve from Advance Truck Parts. Safety First – Turn your engine OFF before beginning any self-diagnosis tests. Today I'll show you step by step how to replace the engine fan clutch Nov 21, 2010 · 1. Specifications: (As picture). Fan should disengage without any air leaking from clutch or air line going to it. com/ 993308 SOLENOID-FAN CONTROL is an OEM part from Kenworth®, VMRS Code: 042-003-024, Manufacturer Part Number: 993308, OEM Part Number: 993308-412. Please note: this is an aftermarket part, the use of other C4R910DC14R8 VALVE-SOLENOID is an OEM part from Kenworth®, VMRS Code: 042-003-024, OEM Part Number: C4R910DC14R8-411. Enjoy our hassle-free online checkout or call to speak to an expert. The solenoid valve controls the airflow, from the vehicle’s system, to the clutch for complete and accurate fan drive engagement. Search our large inventory of New/Rebuilt/Used CAT C15 Engine Fan Clutches for sale. 28 Original price $148. The fan clutch is not engaging. In Stock. Thermal Switch, this will engage the Fan Clutch. Jan 8, 2016 · Usually a bad or failing fan clutch will produce a few symptoms that can alert the driver of a potential issue. Automatic setting seems to work fine though. - 17012151 is the screw vent that is commonly purchased with this solenoid valve. There may, however, be a newer style remanufactured fan clutch available that can replace your HT/S style fan clutch. Mar 31, 2017 · I replaced the solenoid with a new one and it has worked well now for 2 years. Most D12s have them. On mine the green air line runs the fan clutch. NOTE To assure maximum horsepower carrying capacity of the Fan Clutch and to prevent damage to the Fan Clutch, there must be a minimum pressure of 90 to 120 PSI to the Fan Clutch upon engagement. with exchange. Sep 4, 2021 · Helping a buddy with an air leak on his 2017 Kenworth T680 MX13 10sp Eaton auto. You have probably inadvertently solved your own problem. On 1/24/2013 at 7:52 AM, staxx said: I found an open broken pressure switch on the ac condenser that was causing the fan to stay on. Valve-Solenoid-Clutch Fan C4R910DC14R8 - Big Rig World carries Genuine OEM and Aftermarket parts to repair your vehicle at the lowest prices. Fan speed when 2-Speed fan clutch is OFF = 300RPM • HP Draw = 0. Solenoid Valves. 31 In Stock. Some things to check. If not, check the wiring going to the solenoid valve for your fan circuit. Contact Kit Masters customer service to see if this is an option. (509)321-5428 Request Info HTP High Mountain Horsepower C4H940DC147C VALVE-SOLENOID is an OEM part from Kenworth®, VMRS Code: 042-003-024, Manufacturer Part Number: C4H940DC147C, OEM Part Number: C4H940DC147C-411. EASY INSTALLATION | OE-GENUINE REPLACEMENT | FAST SHIPPING. HORTON 993227 - Fan Clutch Solenoid Valve KENWORTH: 993227: 983217: 12: N. 2 wire /powerground. Vehicle overheating. Solution. $65. Advance Truck Parts Detroit 60 Series Engine Fan Clutch Solenoid. I don't have any power coming to solenoid from ECM. This measurement should always be taken at the Fan Clutch air inlet port. many of these fans have a clutch that is air actuated. About: A solenoid designed for precise fan control in cooling systems, enabling the automation of temperature regulation. It spring-actuates when more cooling is the Fan Clutch. - 17012150 is the 1/8in NPT Inline Air Filter. com, America's online marketplace for heavy-duty parts. The fan is either completely engaged or disengaged. The manual setting for the fan won't turn on the fan. Mar 23, 2022 · Hello. com https://www. The heart of the control system The solenoid valve can be thought of as the “heart” of the control system, opening and closing to regulate airflow to the fan drive. I hear air being sent to fan. Box 92 St. OEM #: N/A. Build truck air to 120 psi, turn truck off, count to 10, turn key on. HORTON 993227. Fan is on when engine is cold and off when - Answered by a verified Technician Paccar Fan Clutch on HeavyTruckParts. Same Day Shipping. Nov 21, 2010 · found solenoid!! It was located right in front of 2 air tanks, its right under lover step. Add to Cart. By the way, if you get the injector spill valve code, you have an injector that needs to be replaced. Jul 4, 2023 · Buy Magimaker Solenoid Valve G90-6051 Fan Solenoid Valve Compatible with Paccar Volvo Navistar Truck Replaces 20807261 G90-6051 3611896C1: Solenoids - Amazon. If loosened, the P-clamp must be re-tightened to prevent the wiring harness from slipping through the P-clamp, causing tension on the Fan Clutch wiring. Have also heard of o-rings in the clutch going bad, and. It's a high tech version of a fan clutch in a way but an added accessory. If the ecm coolant temp sensor is reading wrong that could be a problem so use a temp gun and compare the temp at the DM Advantage Two-Speed Fan Clutch alternate between eddy current and spring-actuated cooling. Cloud, WI. Feb 25, 2016 · Just thinking fan clutch solenoid 6 ohms, hope that solves everything. Set the Engine Cooling Fan Clutch Solenoid Valve. 2. C4R920DC14R8 VALVE-SOLENOID is an OEM part from Kenworth®, VMRS Code: 042-003-024, OEM Part Number: C4R920DC14R8-411. Feb 26, 2010 · hello im having an issue with this truck the fan doesnt kick in automatically its a 99 W900 3406E when im in city traffic the truck starts warming up quick and gets to 200 and i hear no fan so i hit the manual to cool it. Replace the fan belt if it is worn or damaged, and tighten any loose connections. The air pressure should be checked in two key locations: before the solenoid valve to ensure air system pressure is correct (‘X’) and before the fan clutch to ensure the air solenoid valve Nov 30, 2015 · Kenworth W900 fan clutch and switch description, location, and replacement. y: Replaced by 993286 High Quality Fan Clutch Solenoid Valve * 2 Pin * 1/8 Inch NPT * A/F: 0813 Inch * 0. FinditParts has KENWORTH Engine Cooling Fan Clutch Solenoid Valve Parts for Trucks and Other Vehicles. Specifications: Ports: (3) 1/8 inch- 27 FPT. or 4 interest-free payments of $33. If the ecm sees higher temp than normal it would leave a hi temp ode and derate or shut down. Like. 4. Spread pins or broken wires inside the insulation are somewhat common on either the fan switch or the solenoid both. Fan clutch off of an MX13 engine pulled from a 2020 Kenworth T880 only run for 16,655 miles, non-wrecked. Part #: TWD VEL032194. 95. May 15, 2023 · Diagnosis. My fan came on and won't go off. The bolt holes are clean and clear from obstruction. should hear an air leak if this is the problem. Aug 8, 2017 · TEST CLUTCH FAN SWITCH AND SOUND Feb 15, 2022 · Check on the dashboard for a fan overridee switch and see if the fan will turn on and off when cycling the fan override switch. Large Selection of Temperature Fan switches. Dec 12, 2019 · LongHaul Larry P. About: The Valve - 4 Way Mini Solenoid stands as a compact and efficient solution for controlling the flow in hydraulic and pneumatic systems. Unplugging switch should engage fan if it isn't already. com/ Here’s everything to know about fan drive controls. But they do not offer a rebuild kit for it, to save Jul 22, 2017 · If the vehicle has been installed with an engine controlled fan clutch, specify the appropriate fan type. Not off. One of the first symptoms that is commonly associated with a bad or failing fan clutch is an overheating engine. fj pe jh qm po gj it zg gq xu