Cold weather has arrived. This post is for those of us who will be replacing their T-stat over Thanksgiving weekend. R213FAQ

http://www.volvospeed.com/Repair/thermect.php
http://www.volvospeed.com/Repair/thermect2.php
http://www.matthewsvolvosite.com/tstat.php

I will definitely buy 6 or 7 inch long 40mm Torx bit.
I will soak T-stat housing bolts the day before with PB Blaster.
I will lightly coat the threads of T-stat housing bolts with Permatex Grey or Ultra-Blue RTV.

First Question
Why don't folks put very thin layer of RTV between T-stat housing and block?

Second Question
Which T-stat do I use 87C or 90C?
http://www.online-calculators.co.uk/...fahrenheit.php
87C equals 188.6F
90C equals 194F

I have experienced problems with 195F T-stats before, so I am going with 87C (190F). Is a 180 degree T-stat available?

 

Go with the 87C

They don't put any RTV because it isn't needed. The rubber seal on the thermostat seals it up.

 

I have learned that the parts dept of Volvo dealerships no longer offer 87C. It has been superseeded by 90C.

I browsed Volvo Parts. They only show 1 part number. I have no idea whether it is an 87C or 90C. My guess is that it is for 90C thermostat, as well??

https://www.volvoparts.com/displayPr...cfm?unitID=114
Thermostat
Model Year: 1997
Model: 850
Part Number: 271664
Your Cost: $ 13.49

I have experienced overheating problems with my other turbo vehicle using 90C. I drove every day in road construction traffic to-and-from work and ended up with a cracked head. I was surprised because the temp gauge did not go above the 3/4 mark.I would like to use a 87C thermostat.

What other thermostats (either 82C or 87C) are available in aftermarket?

 

Im not sure you will have to search.

Are you sure there wasnt' other problems with your other car?

 

I bought my other turbo vehicle back in the early 80's, when car manufacturers were still experimenting with aluminum heads. From the internet forums, I've learned that I wasn't the only one experiencing cracked head problems with this engine. Back in the 60's, before the EPA was established, most vehicles came with 180F thermostats. My 1973 Chevelle SS came with a 195F thermostat and it ended up consuming anti-freeze -- now that I think about it, it probably had a cracked head, too.

In summary, all three of the vehicles that I've owned with a 195F thermostat, ended up consuming anti-freeze. The other three that I've switched over to a 180F thermostat did not -- and all three of them have over 170K miles. I am very reluctant to use another 195F (90C) thermostat, especially in a turbo-ed engine.

http://fcpgroton.com/volvo850cooling.htm
271417 - Thermostat and O Ring - 87 Degrees - $9.00 - Vernet (OEM)
271664 - Thermostat and O Ring - 90 Degrees - $9.00 - Vernet (OEM)

 

This morning, I ordered...
http://fcpgroton.com/volvo850cooling.htm
271417 - Thermostat and O Ring - 87 Degrees - $9.00 - Vernet (OEM)

FCP Groton. D.B.A. Foreign Car Parts of Groton, Inc
Foreign Car Parts of Groton, CT
734 Poquonnock Road
Groton, CT 06340
PHONE: 877 634-0063
FAX: 860 445-0511
E-MAIL: info@fcpgroton.com

Price with Shipping was $14.50.

I will verify that it arrives in a Calorstat/Vernet box and that it does have "87" stamped on it.
If not, I will return and try these one of these vendors...

http://www.autohausaz.com/search/pro...tnumber=271417
http://www.autopartsguru.com/item.ww...partno=1291552
http://catalog.masterautoparts.com/i...partno=1291552
Masterautoparts.com
7001 Reseda blvd
Reseda, CA 91335
Phone us: 1-818-344-0834
http://www.euroautoparts.biz/Cooling.htm
European Automotives
1119 Highway One
Lewes, De 19958
(888) 891-3445
sales@europautoex.com

Otherwise, I may just purchase what I've used for years -- Stant SuperStat
http://www.stant.com/brochure.cfm?br...ocation_id=168

 

I was not able to locate a long 5 inch T-40 Torx bit at Sears (Craftsman) or NAPA Auto Parts. I found one here...

http://www.mcmaster.com/
(630) 600-3600

Enter page number 2609 in search field.

http://www.mcmaster.com/ctlg/DisplCt...CtlgPgNbr=2609
3/8" Square Drive, Long
T30 5" Length 6939A84 13.84
T40 5" Length 6939A87 13.84 <--
T45 5" Length 6939A88 13.84
T50 5" Length 6939A89 13.84

 

Let us know how it goes when you get it done.

Thanks for the info!!!

 

This afternoon, I found my 190F thermostat from FCPGroton lying on my door step...
http://fcpgroton.com/volvo850cooling.htm
VOL-271417 where the sales rep wrote Wahler on the packing slip

It came in a box with red sides and blue top and bottom in white letters,
Wahler Thermostat Made in Germany and Part Number 4272 87D stamped on the front.

It has "Wahler, Made in Germany" inscribed along the top, and "87" inscribed on the bottom.

It looks identical to the one in this picture,
http://www.volvospeed.com/Repair/thermect2.php
http://www.volvospeed.com/Pics/repai...mostatECTR.jpg

I had to rotate the air bleed hole closer to the middle.

Last week, I also purchased a 180F thermostat from Stant SuperStat
http://www.stant.com/brochure.cfm?br...ocation_id=168

It comes in a yellow and blue box with "Stant" in red letters. Part Number is 45378. Stant offers a rubber seal which must be ordered separately.

Comparing to the Wahler, the frame appears to be heavier and thicker and made of stainless steel. The spring is much thicker, as well. If I decide to use it, I will need to drill an air bleed hole.

 

The Wahler should already have a bleeder in it. We use them at work all the time. They are good.

 

Sorry for the confusion. Wahler has air bleeder hole. The Stant does not.

 

Ok then like I said the Wahler is a good brand we use them everyday and never have any problems.

 

Another thought...

Rather than draining coolant from radiator, I found it much easier to drain from the block...
http://www.volvospeed.com/Repair/thermect.php

I put jack stands on rear part of engine sub-frame. There is a coolant drain petcock on the rear of engine block on the passegner's side. Loosen with 13mm box-end wrench. Insert and slide a 3/8 inch rubber hose, 2 feet long, over petcock. Place other end in a wide-mouth plastic container, like 1 gallon Tropicana Orange Juice Jug. By hand, open petcock to drain about 3 quarts of coolant.

 

Also, I replaced my Engine Coolant Temperature (ECT) sensor.
http://www.volvospeed.com/Repair/thermect2.php

Part Number 9186486 listed as 9186486-8 IAT sensor, $63.40 at my local dealership.

It is incorrectly listed as an Intake Air Temp (IAT) sensor. This is the correct part, as the old one on my car had the same part number stamped on its side.

I had a very difficult time disconnecting the old electrical connector. The plastic cover would slide, the wires would not come apart. I pried up on the flip-up door on the sensor side of the connector. Then, I was able to gently use pinch-nosed pliers to pull apart the wires.

 

what are the steps I need to take to replace my coolant temp sensor? how about my thermostat?The torx screws are hard to remove, I should spray them correct? Help would be appreciated......

My hext question is that I just purchased a driver side headlight and it looks like their is condensation building up inside the lens? what can I do to prevent that?

 

The ECT sensor is located under the neck of thermostat housing. Unfortunately, you have to remove thermostat housing in order to get flare-nut wrench on ECT sensor. On my car, PB Blaster was not needed, just a long torx bit for proper fittment.

Follow these procedures...
http://www.volvospeed.com/Repair/thermect.php
http://www.volvospeed.com/Repair/thermect2.php
http://www.matthewsvolvosite.com/tstat.php

The most time consuming task is disconnecting the electrical connector. I was not familiar with the flip-top doors on each end of the connector.

Regarding your problem with moisture in headlight lens -- start a new seperate post. Under close examination, you may be able to solve problem with clear Permatex RTV.

The most difficult