2004 T6 DIY Thermostat Fix - Easy Tutorial

Post by **kickin_it** » 21 Jan 2014, 15:46

I recently had the pleasure working on a 2004 XC90 T6. The issue at hand was a bad water pump so I replaced everything I took off: timing belt, accessory belt, tensioner, pulley, water pump, thermostat, and the dreaded nipple on the thermostat. I browsed this and other Volvo forums and found some great ideas for the housing fix just no step-by-step with part numbers. I decided to take notes and pictures throughout my repair which turned out pretty damn good I must say.

I started by removing the cover of the housing, I suppose you could just remove the housing as a whole. The cover is held on by 3 - 10mm bolts.

: T-stat cover - 3 - 10mm bolts; thermostat.jpg (195.34 KiB) Viewed 7523 times

T-Stat cover and gasket removed with bolts.

: T-stat cover w/ bolts; thermostat_1.jpg (148.56 KiB) Viewed 7523 times

I chose to remove the sensor from the housing, others may choose to remove the housing with sensor in place. I broke the nut loose with a 3/4 inch but it may be a 19mm either should suffice, break loose and spin with fingers.

: Sensor; used 3/4 inch wrench to break loose; thermostat_2.jpg (167.76 KiB) Viewed 7523 times

I then removed the housing from the motor by removing the 4 - T40 bolts. I used T40 socket and ratchet.

: Housing; T40 bolts; thermostat_3.jpg (157.58 KiB) Viewed 7523 times

Housing removed with sensor removed and bolts.

: housing removed; thermostat_4.jpg (134.78 KiB) Viewed 7523 times

Motor with thermostat and housing removed with sensor still attached.

: motor; no t-stat housing; thermostat_5.jpg (152.99 KiB) Viewed 7523 times

Here are the parts I picked up from the blue big box store, I went to the orange but no wanted to help. I would rather use Kobalt tools than Husky anyways.
Parts Needed
2 - LFA712 Elbow
1 - LFA776 Adapter(Bushing)
1 - LFA716 Pipe
1 - LFA298 Hose Barb
1 - Roll of thread tape or wrap
Tools Needed
Clamp or Vise
11/32'' Drill bit
1/8'' pipe tap
Drill

: parts; thermostat_6.jpg (183.47 KiB) Viewed 7523 times

I am not sure of the size of the drill bit but I first drilled out the broken plastic nipple. I then used the 11/32" to drill a larger hole where the nipple used to be. I then used the 1/8" pipe tap to thread the new hole. This was the trickiest part and probably the most important. My tap was not tapered so I actually used a 3/8 bit to widen the mouth of the hole about 1/8 of an inch deep to allow the tap to sit in the hole before tapping. I C-clamped the housing to the table and started twisting tap using crescent wrench.

: tap; thermostat_7.jpg (185.75 KiB) Viewed 7523 times

I then attached the pipe and one of the elbows. I used thread tape/wrap on every thread. I then attached the elbow and pipe to the housing and tightened. Make sure to pay attention to the direction of the pipe, you want the hole for the sensor to the lower left hand side and the pipe pointing at you. I replaced the thermostat with new o-ring and a new gasket between the cover and housing. I decided to install as one unit. I reattached the sensor and tightened it down.

: t-stat; thermostat_8.jpg (141.12 KiB) Viewed 7523 times

T-Stat installed with sensor and new fittings attached. Note: there is a plastic piece on the back timing cover that will need to be modified. The easiest and best looking would be to use a dremmel or something similar. I did not have one on hand and opted for some pliers and just "snapped" the plastic. This is required or the housing will not sit flush.

: installed t-stat; thermostat_9.jpg (128.68 KiB) Viewed 7523 times

Next step is to attach the timing cover. The new brass pipe will fit into the existing hole without any modifications. Prepare the rest of the fittings by placing the adapter and the barb together, again using thread wrap. You must first attach JUST the elbow to the pipe sticking through the cover, tighten it with the elbow pointing upward THEN attach the adapter/barb to the elbow.

: fittings; thermostat_10.jpg (146.58 KiB) Viewed 7523 times

Here is a shot after just the elbow was installed and tightened. Note that the elbow is pointing upward in the direction the hose needs to run.

: elbow; thermostat_11.jpg (115.1 KiB) Viewed 7523 times

A shot after the adapter/barb attached to the elbow and everything is tightened down w/o hose attached.

: barb fitting; thermostat_12.jpg (173.55 KiB) Viewed 7523 times

I used the trusty screw clamps and used the existing hose without cutting or modifying the hose in any way to the expansion tank and to the nipple we just installed.

: install complete

And you are done! I hope you enjoyed the tutorial and I was able to save you some money. All in all I spent less than $20 on parts and I already had tools needed on hand. Any questions or comments please leave below, thanks guys.

Post by **matthew1** » 21 Jan 2014, 16:16

Beauty writeup, Kickin It. Scheduled for addition to the Volvo Repair Database in the XC90 section.

Post by **kickin_it** » 23 Jan 2014, 12:20

Thanks Matthew. I am working on another tutorial for T6 timing components replacement. Tutorials should work with S80 T6 as well as the XC90 T6.

forelsol · Post by **forelsol** » 16 Feb 2014, 20:20

Hey Man - Sweet write up. I broke off the thermostat housing nipple early today and need to rebuild the thermostat housing. Anyway - this is super helpful! Thanks again.

dustydawg89 · Post by **dustydawg89** » 29 Sep 2014, 13:54

Is this the same process for a 2008? Thanks in advance!

Post by **songzunhuang** » 27 Jan 2015, 20:16

Argg, wish I saw this earlier.

I ended up buying the aluminum replacement step from URO. As it turns out, it's slightly smaller in diameter than the original plastic nipple so now I have a leaky connection at the coupler. I thought it my be that the o-ring in the coupler was getting old, so I ordered a new expansion tank hose - which comes with a coupler at the end. I'm waiting on that part now.

If that doesn't work, I'm sending all the stuff back and doing what you did.

Here's my writeup - https://www.matthewsvolvosite.com/forums ... 10&t=68114

Post by **songzunhuang** » 29 Jan 2015, 21:36

Well, my new expansion hose came in the mail and I tried to put it on the metal URO nipple. Epic fail. The URO part is just too small a diameter to get a good seal.

I needed the car so I got 1/4" fuel line and a 3/8" brass elbow and put it in place temporarily, but with this temporary setup, I can't get the front timing cover on. However, it'll have to do until I can do this permanent fix.

This is the best way by far I've seen by far.

Post by **songzunhuang** » 07 Feb 2015, 11:25

Well this fix has worked very well for me and it's been about a week. One thing different for me was that the 1.5" pipe wasn't long enough. I could spin the barbed portion around because it was blocked by the timing belt cover. I ended up using a 2" piece of pipe and that fixed it right up.

Also one other issue I had was that the 90 degree elbow in the housing had to be modified slightly. In order to thread the elbow all the way down, I had to file of some of the lower corners of the brass. They were interfering with a molded hump on the housing that was very close to the tapped hole for the elbow. I had to file about 1/8" off.

Overall a wonderful fix. I'm busy sending all the parts back from the previous efforts. Thanks again.

Wichitas80 · Post by **Wichitas80** » 02 Nov 2015, 09:04

Having the same problem and I’m in the middle of the repair.

kickin_it said

“Note: there is a plastic piece on the back timing cover that will need to be modified. The easiest and best looking would be to use a dremmel or something similar. I did not have one on hand and opted for some pliers and just "snapped" the plastic. This is required or the housing will not sit flush.”

Kick_it is correct. It won’t fit without trimming that piece of plastic. My concern is that the piece of plastic is there for a reason. Should I be concerned about trimming it?

Post by **shiloh51933** » 27 Feb 2020, 08:55

Thank you for posting your write up, excellent work. I'm swapping out the thermostat housing, thermostat, temp sensor, every gasket, hardware, hoses to coolant reservoir and upgraded the plastic elbow with a brass elbow from IPDUSA.COM. My question to you is this: Did you lose a lot of coolant when you popped off the Thermostat Housing w/thermostat?
I was thinking of possibly draining the entire system. The T belt, tensioner, idler, water pump was completed at last interval and isn't due again.