Volvo 850 Thermostat and Engine Coolant Temperature Sensor Replacement

[@pulsing1982]

thanks, very helpful! for those not aware, your CTS is an integral part of your 850's engine management system. Currently mine (replaced 4 years ago) is reading low, the front ceramic seal has gone (the wires are hanging loose out the front). As it's reading 'low', it's telling the DME that it's not up to operating temp... so the car is running rich and using more fuel than it should. I'll replace this with a genuine Volvo part If you're replacing your thermostat, you should do your CTS as well. Hope that helps.

[@troyoverton14]

Thank you for making this video. I used it for researching a V70 and it was quite helpful.

[@myRatchets]

np, glad it was of help to you. Cheers

[@iribwa]

Thank you for making this video. This was very helpful to me. My sister has the same problem on her Volvo 850.

[@myRatchets]

Glad you got it working, sorry I missed your first comment.

[@apheus27]

Thanks a bunch for the video. Helped a lot!

[@rushenge]

Thanks very much for this video.

[@buddy6922]

after my 94 850 gets warm its hard to start Ive ordered the sensor and thermostat, I dont thing it mentioned an oring, am I going to have to order that as well, Im waiting for my parts.

[@mercedesortega44]

i got a 95 850 turbo, I just changed a bunch of hoses in it and it's still over heating only after a while of running around town. The fan does turn on, could it be the thermostat and or the censor? I could really use some ideas I am getting a bit desperate in this Las Vegas heat!! And is there a specific way the thermostat needs to be put in the chamber?!

[@jlee3925]

Great video 👍👌

[@tigerman4]

replaced the sensor and runs fine now

[@knakker36]

I am having a little trouble with my Vovlo 850 2.5I-20V GLT (1994) At some point I noticed a big puddle under my right front tire (passenger side). I checked it out and found out it was the coolant. I filled it up with new coolant and started the engine. Everything seemed to be fine. I watched the engine run for 10 min. I noticed that the level of the coolant actually increased which surprised me. I then took it for a short drive around the block. When i stopped the car and took a look at the level of the coolant, the coolant at that point was spitting out of a crack on the coolant reservoir cap. The engine seems to run perfectly fine. Do you think this has to do with a defect thermostat? What is your opinion on this? Kind regards, Rick

[@volkerzimmermann879]

Since this comment is from 3 years ago you probably already found a solution to your problem, but it might be a leaking head gasket. Robert DIY has a video explaining how to identify that problem, and the symptoms you describe match almost exactly. These engines apparently run really well even though they have a blown gasket, but what happens is that pressure from the motor gets into the coolant system and pushes the coolant into the reservoir, leading to a cracked cap and coolant spilling out on top.

[@tigerman4]

I think its 19mm or 3/4 will work on it.,,,did you replace it because the gauge wasnt working ? or because the fan wouldnt turn on ? my v70 electric fan wont kick on , I replaced the relay and thermostat , but broke the stupid temp sensor trying to put the new one in....so I put the old one back in....fan still not working....but runs when I run 12v to it , both speeds work fine , the only thing left is the sensor again ( I will get a new one today and not tighten it up as tight this time )

[@allenmayes638]

having the same fan wont run on my v70 was the sensor your answer to the fin working

[@mabskha1808]

So was your temp guage in your car not working then???

[@andrewquintus3611]

great video. though I can't find the sensor on a 98 s 90

[@coolguy125]

Hey I got a question we have the same car and the car will start fine but about 5 mins of driving it will start to miss really bad and stall out , weve had a lot of repairs done and nothing fixed it . new MAF oxygen sensor , fuel filter, and was wondering if you had a problem like this out of yours? We cant figure out what its problem is. Thank you

[@myRatchets]

Sorry I only had this car for a few weeks and in general not that familiar with Volvo's. Best advice I can give you is to take it to an independent shop that specialized on these cars and ask for a proper diagnosis and before doing any repairs ask them if they will refund you at least the labor for miss diagnosing and/or replacing parts. GL

[@coolguy125]

Alrighty thanks man

[@pulsing1982]

I had all that 4 years ago, I'd already done the basics (rotor, cap, leads, plugs), it had been running warm so I had the auto electrician replace the CTS and T'stat; he also replaced the MAF and Fuel Filter. Solved the issue. You may want to check the crank position sensor. Cam position sensor also fails, though that's more about starting than fail during run. Hope that helps. Check out the forums at volvospeed.com

[@joe-jz1dg]

Car starts after 10 second crank and when i hit the pedal right after it will stall. If i shut it off 15 min later and re start it will crank up right away every time. Tho at idle it sounds chopy.. What could this be

[@shortboarder]

Non turbos are 2.5 liters!

[@vivianamoreno910]

I.HAVE A 1997 850 VOLVO AND ALL OF THE SUDDEN THE ANTYFREE WAS LICKING I WINDER IF IS. THA TERMUSTATUS?

[@SexcAzn100]

You need to find out where the antifreeze is leaking from. It's very rare for leaks from the thermostat to happen. Most commonly it will leak from either the upper or lower radiator hose, because those rubber hoses just don't last very long. Also check the hoses that connect the radiator to the expansion tank (where you check the fill level and add fluid) You might also check to see if its leaking from the actual radiator. I had a slow radiator leak on my 98 S70 (very similar to your car) and had to replace the radiator and it wasn't easy at all but I did it with help from several Volvo forums. You need to crawl under the car and find out exactly where its leaking from, and don't drive it until you do or you can very easily overheat the engine.

[@andrewbergeron2427]

Darren Lee hearter core