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Replace Thermostat Volvo 850, S70, V70, C70 or XC70

Ready To Replace Thermostat ?


thermostat for Volvo 850 The thermostat is located between the engine and the radiator. The thermostat acts as a valve that stays closed during engine warm-up. When the thermostat is closed, it prevents coolant from leaving the engine and circulating through the radiator. When the engine gets warm, the thermostat’s spring valve opens, allowing coolant to circulate through the radiator to be cooled. If your Volvo is overheating (it failed closed) or the temperature needle is no longer reaching 3 o’clock (it failed open like mine), you need a new thermostat.


  • ratchet and 10mm socket
  • ramps or jack and
  • jackstands to get the front of the car off the ground
  • blocks for the rear wheels
  • torx bit size T40, long
  • WD-40
  • bucket to collect coolant
  • funnel


drain the coolant to below the thermostat level Raise the front of the car using a jack and jackstands, or if you have ramps like me, with ramps. Put the transmission in Park, activate the parking brake, turn off the ignition, and block the rear wheels. If the temperature needle is anywhere but ‘cold,’ wait an hour so that the coolant is cools. Remove the big black plastic radiator splash guard (one bolt on each side, 10mm I believe) under the radiator. Remove the cap on the coolant reservoir, then place the bucket under the plastic radiator drain valve. This can be found on the driver’s side, bottom edge of the radiator. remove two torx bolts on the thermostat housing Drain about two liters of coolant into the bucket, then tighten the valve back up. Be very careful with this valve… it’s plastic and they have been known to break easily.

The next step is to loosen the two torx bolts that hold the thermostat housing together. Two things to note: spray some WD-40 or other loosening agent on the bolts, and, you may want to take off the aluminum fuel injector rail guard to get a better look at the hidden torx bolt. Ok, on to the details… One torx bolt is easy to get two… the other is, well, difficult. I got a torx bit and used that on an extender with a ratchet, but the bit was forced to contact the bolt at an angle that almost caused the bolt to get stipped. I’d strongly recommend getting a long torx bit like this. the thermostat housing with the top off

You don’t need to remove either of the hoses that connect the housing to the radiator and coolant reservoir. With the torx bolts off, the top of the housing comes right off, as does the thermostat inside. Take it out and put the new one in. Put the top back on, tighten the torx bolts, and pour the coolant back into the coolant reservoir. Don’t forget to make sure the reservoir cap is put back on and the drain valve is tight. Put the splash guard back on and you’re ready to go.


Like I mentioned above, you can try to use a short bit to get the difficult torx bolt out, but my strong recommendation is to use a long one, or if you have the grip of Arnold Schwarzenegger, a T40 torx driver. While you’re replacing the thermostat, you might as well replace the coolant also, flushing the system in between. I didn’t because I didn’t have any antifreeze with me, but I’m going to pick some up in a week or two.

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For my 2000 S70, the radiator drain bolt is 1/2″.

I have a 2005 xc70 (175k) that is very slowly leaking (seeping) coolant around the thermostat. I suspect that all I need is a new gasket for the housing, but I am wondering if I should replace the thermostat (due to milage) while I am at it? I also see that IPD sells the entire housing kit. I don’t have any issues with overheating, but she’s not getting any younger.

If the temperature drops below 25 degrees my 2001 V70 Volvo starts putting out less heat, at 10 degrees it puts out very little heat. At this temperature the gauge only moves up one degit not to the 3 O’Clock range. What could be wrong ? Do I need a new thermostat ?

My 1995 volvo 850 starts up and it gets hot really fast but if I let it idle it will get even hotter and will drop immediately after I start driving it again. It isn’t like a minor drop in heat. It goes from about 1/3 of the way up the gauge to about 2/3 the way up the gauge and then back down to 1/3.

Any idea what this is? I think my head gasket is cracked but I’m not sure if something is broken with my thermostat also.

Thanks, it was very helpful to know what to expect and this turned out to be an easy job. I’ve got a 2000 V70 (XC-AWD 2.4l) and here’s what worked for me.

As others have noted one of the T40 screws is blocked so I removed the plastic piece that covered the timing belt (held by two T30 screws) and was able to get at it easily. I used a Torx ‘socket’ with a ratchet and extension to remove and retighten the screws.

I didn’t drain the radiator but I put a plastic basin underneath the car and that caught just about all of the fluid that escaped, which wasn’t much.

Thanks Robert J. I’ll pass this along to the Volvo forum guys.

I bought the snapon torx
FTXEL40E2XLNG TORX BT directly from Snapon. It was $10 with free shipping. I felt getting a good quality bit that would not strip the torx bolt might save me a lot of $ if I ran into trouble on my 98 V70.

I have a Volvo S90.
I live in Malaysia where the weather temperature is constant throughout the year at 80 deg. Centigrade.
Recently the engine got hot and I ended up with a top over
haul. I am thinking of doing away with the thermostat.
Is this OK

kendash2000 says:

BTW, P0128 code, in addition to slow warm-up and limited heat, the fan would sometimes run on start up and more than 5 minutes after stopping, even in 30 degree (F) Penna. winter

kendash2000 says:

98 V70 turbo, 190k. Not a gear head, but have done some car work. P0128 code, slow warm-up and limited heat. PB Blaster on bolts. Must use long torx on back bolt. Do not need to remove fuel rail, but need to move fuel line slightly to get leverage. Bolts came out with some effort, but better than expected. Old T-stat was broken on one side. Used a Motorad Fail-Safe® thermostat, $5 more than other. Replaced Temp Sensore (really easy) and used anti-seize compound.

Thanks everyone!

Replaced my thermostat this past month. Probably overspent, ~$70 from amazon, ~$70 from FCPeuro, and distilled water. Still less than the dealership.

No ramp needed. Left cowling on, and snuck a deep wall socket up the small hole towards the driver side. “Great Neck 2035 13Mm 3/8 Dr.Wall Mtr Sckt”

Used a T30 bit to take off the timing belt cover.

World’s cheapest socket, a long driver bit, and a box wrench angled on the end of the rachet for leverage got the bolts off. Didn’t need the PBblaster. Skipped using a hand impact driver to loosen the bolts, as I didn’t figure out how to set it until later (practiced on wood board).
“Great Neck PSO40 40 Piece 1/4-Inch and 3/8-Inch Drive Socket Set”

Fcpeuro had

I got spare thermo housing bolts and a petcock, but didn’t need them:

i own a 2000 v70. can i run the car if take off genuine turbo. car has done 92k.

Roger Heim says:

How do I flush and refill the coolant system on my s70 1998?
I do not see a filler area other than the overflow tank.

After all this advice I still managed to strip the second torx bolt. Any suggestion on what I can do now? I have a 1998 S-70. I was using a long t-40, I sprayed the bolts with WD-40 but I must have had a bad angle on the bolt.

Just done 1999 V70. It was easy, if nerve-wracking. Didn’t siphon off coolant, just covered alternator with a plastic bag, and no trouble with screws – just squirted with WD40 (AA equivalent), then used torx and pliers! Nice warm car again. Bit confused by ‘bleeder valve direction’ on another site, but then found my new t’stat didn’t have one. Thanks for advice!

I have a 1998 volvo s70 an one day as I was driving my car over heated an started smoking an wen I turned the car off to cool down it made a sizzle sound as I poured the water in…then wen I went to start it it wouldnt start…so finally it,started an I left my hood up cus I,thought I needed a jump…water start shottin out of the car from the radiator all over the engine…mamaged to get home an next day got radiator an spark plugs fixed the guy told me that I have a crack head gasket….vecasue after he replaced the radiator an started the engine water started shottin back up an now car wont start….any help on wuss wrong with the car

Christopher says:

Help! Used this tutorial to change thermostat and car STILL LEAKS …. any suggestions? Please help.

BikerDoug says:

Couple of suggestions I’d like to add regarding this thermostat replacement:
1. Use a good penetrating solvent on the thermostat housing bolts (I like “PB Blaster”). Soak both bolt heads liberally and leave it (preferably overnight);
2. This post has several methods for getting to the rear Torx/Star head bolt. I used the long 1/4″ drive T40 in a set from Harbor Freight ($12.00 or so, part #68015) and did not have to remove anything else or move the fuel injector line. Worked fine, but had to really muscle the bolts loose;
3. Other posters agree to leave the plastic hex-head radiator drain plug alone, as it breaks easily – they are not lying. I’m seconding their comments. Just take the lower radiator hose loose and let it drain that way.;
4. Replace the thermostat with the Wahler brand (OEM, eEuroparts, about $9). It’s worth the extra cost over the parts store brand, as when (Yes, “when” – they all fail eventually) it fails, it does so in the open stage;
5. Replace the thermostat housing bolts. I paid 58 cents each (again, eEuroparts) for new bolts. I sprayed the threads with dry teflon and followed that up with anti-seize. They won’t weld themselves in again. Good luck.

My wife’s Volvo s70 2000 starting overheating. It would stall and shudder after getting off the freeway she noticed it was running very hot. Last weekend I checked the coolant level and found it was bone dry. I filled it up but on Friday while my wife was driving smoke started pouring from the engine, she pulled over and later manage to get the car home.

When I got home I found there was no coolant again, I first thought it must be a leak. I filled out the coolant again and drove the car around. I could not see any sign of a coolant leak though. I did not suspect the thermostat at first because the coolant was vanishing. I guess it was evaporating from the heat?

I have done a little car work in the past on US cars and was a little daunted by stories I’ve heard about working on European cars. However thanks to this blog it was easy!!! I ran up to the local auto store and purchased a new thermostat w/ seal for about $10 and a set of Torx heads for $8 as the set was only $5 more than a single T40. It actually worked out buying the set as I needed to remove the timing belt cover which needed a smaller Torx. I probably could have worked around it but it was a 10 second job to remove the timing cover and gave me full access to the thermostat housing.

I decided to remove the hose attached to the bottom of the radiator for draining the fluid which was not the best thing for me as I had trouble wiggling it back on and ended up draining everything. No biggie though. I guess I should have stuck to this article 🙂

I then removed the timing cover and two bolts on the thermostat housing, took out the old part cleaned the housing, put in the new thermostat and screwed everything back together. It took no time maybe 10 minutes, most of that time was me trying to find my tools.

This was just the latest in a long list of weird issues we have had and were ready to dump the car. Thanks to this blog I can hopefully spend a little more time picking out our new car.

Thank you!

’98 V70. For some reason not very much coolant drained from the drain plug, so it came out when I unbolted the thermostat housing. Still super easy. I ended up using a T40 wrench with a t-shaped handle at the top for more torque. Definitely glad I had the long wrench instead of just a socket.

’99 V70R. No jacking and no draining for me. Undid the top timing belt cover to get access to back bolt. Put a plastic bag over the alternator, undid the top hose and held it straight up and lost maybe 1/2 cup of fluid. Replaced thermostat, put it back together. 10 minute job.

minus 12 outside and changed it in 10 min.
long T40 a must. back screw was tricky but not impossable.

Andres Silva says:

Thanks so much for the tutorial. I had a very difficult time removing the rear torx bolt since it was stripped, but was finally able to get it out. After the bolt was removed it was a very simple procedure to finish the thermostat change. Thanks MVS for the help!

Martin Bradburn says:

On my 2002 V70 XC, there was no need to remove the splash guard under the radiatior (I discovered this after the fact). There is a hole through the splash guard on the drivers side. An allen key (or wrench) can be used to loosen the drain plug. The firewall side torx bolt was made more accessable by taking the timing belt cover off. If I would have known about the drain hole this would have been a 20 min job.

My ’99 V70’s temp gauge goes to full cold when we are driving down hill on a cool day. Is it possible that the cool air flow over the engine can cool the coolant down even if the thermostat is closed? Is it possible the stat is stuck open? Aren’t stats “normally closed” valves?
Any thoughts…

Thanks for the forum. This was my first time doing any mechanical work to my 2000 S70 SE/GLT. I bought the Part for 13.98 (Autozone w/gasket). Removing the timing belt cover is the best way, after checking the layout of the replacement. I recommend taking the extra time and draining the radiator, then removing the thermostat. I didn’t and leaked on my garage floor; went slow as to hear the dripping and grabbed a bucket. After the run-off then I unbolted (WD40) the housing and replaced. Screwed back in, clipped and bolted timing belt cover back on and was done. Refilled the expansion tank to in between min and max. Started w/ no problems. Driving after 36hrs and a much faster warm up and the heat is blowing hotter, quicker.

Thank you so much for this forum! My Husband and I just changed out the thermostat on our 2000 V70 XC AWD SE. Garage would have easily charged us $250 for a job that cost us $20.00 for the new thermostat and gasket. Had we had known that the timing belt cover screws were T30, not T40 like the thermostat, it would have taken 10 minutes for this job. Took an additional 30 minutes to run to Autozone for the tool. Thank you again everyone for the helpful and money-saving information!

George 747 says:

2001 V70 XC. Torx came out nicely. Didn’t need a long bit. Took a little brain power to get the splash guard off. It had 2 Torx & 2 bolts. Something was still holding it in place and they I finally saw I simply had to release pressure on a plactic piece with a long screwdtiver & it came out. Later I saw there was a hole already in it to gain access to the drain. Wife picked up the part while she was out running errands and darn if it wasn’t missing the gasket. Off to the store in a few. I hope this fixes it.

Hi i have volvo v70 it is overheating very high and its crack the head, so we change the dead and headgasket even we change termostat twice, but it still overheating, its made me very sad with all i have spend on it, now we showed it to mechanic he said again there isn a problem with the engine, please give me advice on this matter, it will be great if send me email on

First, I have decided that I’m an idiot. Here’s why, I stripped the 2nd torx bolt head, then broke off the easy out that I drilled into the stuck bolt, then in a fit of idiocy I diconnedted the gas line and pulled out the fuel injector to try and get increased access to the bolt. The bolt is still stuck but now I’m wondering if I’ve completely screwed up the fuel injection. I live in a small town that only has one mechanic and he charges triple the average so I’m wondering before I take it to him to replace the thermostat if I can easily just put the fuel line and injectors back in or if there’s a certain procedure.

Another great post. Helped greatly. However, just as I was about to pop down to my local DIY store for the torx extension I realised with a little endeavour by simply attaching a vice grip to the top of the torx key (T-shaped without one lug) the two bolts were easily released. No special tools required. Not to say that if yours are ‘welded’ on it might be different, but just to show that it can be done. Thank you.

tyler coffey says:

I appreciate this forum and the advice.I have an s40 and changed my thermostat in 20 minutes! The t40 torx was essential, on a s40 to replace the tstat it is easiest to take the timeing belt cover off, to do this you will need a smaller tork bit, possibly 25,i luckliy had one. Couldnt find the drain valve on bottom of car so when i took the old tstat out i let the remaining antifreeze fall out. I bought a new tstat,wd40, seal gasket (sold sepertly) and a t40 tork bit, $13.48 all together! Sure beats the dealership!!

Thanks a million

2000 S70 non-turbo: Just replaced thermostat. I agree with Mike, removing timing belt cover is easy, and provides full access to rear bolt on thermostat cover. Did not need long T40 torx driver. The splash guard on the 2000 S70 has a hole (1.5 inch diameter) directly under the radiator tank drain (left side). No need to raise car. I was able to loosen the plastic drain plug (carefully) with a deep 14mm socket. With engine cool, loosen until coolant runs, into a clean pan. No need to remove plug completely. Drained about 1 liter. Gently re-tighten drain plug. This is an excellent post. Thanks!

2000 V70 XC, I didn’t need the long torx as well and there was no need to remove the coolant, total of 8 min to change from start to finish.

Didn’t need the long torx at all on my 2000 S70. The one torx is hard to get to because of the black plastic housing over the engine that covers the belts. It can be quickly moved out of the way by removing the two torx screws on the top and popping the clip on the side (30 seconds max). You can just move the cover a little and have full access to the hard to reach torx bolt.

Good stuff. The long T-40 driver bit cost me $3 at my local tool house. S-K offers a nice socket style for $38, but I just grabbed the cheap hex bit with a c-wrench and called it good. PB blaster for 20 minutes and a few light taps with a punch got the bolts ready to come out with no drama. I found that I didn’t have to jack the car at all; just pulled off the splash guard and stuck an antifreeze bottle on its side with a funnel stabbed into it, used the plastic drain fitting with no problem. I pulled the small hose to the reservoir off, as it took some twisting to get the top part of the housing off. Easy fix; car warms up quickly now. Thanks, everyone!

Johan Locke says:

I know nothing about cars and replaced the thermostat with this advice within 20 minutes. Thanks a million to all contributors! 2009 Aug 7

Matthew R. says:

Agreed that you must use the long T40 bit, but you must also watch out for the following. I have also heard of the hidden torx getting seized and snapping making for a very very expensive thermostat change. Do the easy one first, and gauge the force required to loosen it, if the hidden one requires significantly more force before it moves you may want to do the following procedure to avoid snapping the bolt.

Get a very long and thin high speed drill bit, now this may sound crazy, but you need to actually drill a hole into the thermostat housing/cover just below the head of the hidden bolt to gain access to the shaft of the bolt so that you can introduce lubricant or penetrant to the area that is actually seized. This area is solid aluminum and you wont cause any damage as long as you are very careful not to drill into the actual bolt. Once the hole is done all you need is one of those red straw adapters to your choice of spay to lube the seized area before trying to loosen the bolt. Good Luck!

I also replaced my thermastat on an emergency basis. The t-stat stuck in the closed position and my car overheated. Here is my two bits:
1) I agree with the LONG torx driver bit. Otherwise there is a good chance of stripping the head.
2) Try a hand-held impact driver to loosen the two stubborn bolts.
3) It is possibe to drain the coolant without a ramp or a jack stand. Simply detach the lower radiator hose from the radiator. That way, no need to crawl under the car, no need to remove splash guard. No fear of damaging the plastic drain plug.

I had I similar problem but I found siphoning the coolant out to be very useful, very little mess and if you use a clean bucket the coolant can be reused (my coolant was only put in two days before so was worth saving), no jacking needed.

Siphon out the expansion tank, so you can release the top radiator hose then stuff the pipe down the inside of the rad to the bottom, and then drain the rad.

Pulling the coolant up a clear pipe (fish tank hose or wine making hose), till near the top, and then pinch off the pipe, and releasing when low down in a bucket saves getting a mouth full, best do this when the coolant is cold (obviously).

The long T40 bit (a $15 investment) is a must!

1. Definitely use some W-D40 on the bolts wait about 4 min (get a beer).
2. Pop off the fuel rail.
3. Loosen the easy access bolt first then the harder to reach one.
4. Pull out old thermostat….replace with new. (replace bolts) then attach fuel rail
5. Fill the reserve and go.

Est. time 11 min. It’s that easy!

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