850 thermostat fail. OEM.

Post by **Ben850** » 16 Oct 2014, 14:54

This is the Whaler that was in my wagon last year. I had not realized it looked like this.
The car did sit for three months while the weather went to nearly 20 below zero.

A full level of Zerex mixed 50/50 with distilled water was in the system.
I did end up replacing the radiator after noticing drips at the time of the silicone plumbing upgrade.

So the thermostat and ETC were also replaced with OEM Valeo and Whaler without a second glance at the old parts until recently.
I don't usually throw out old parts for reference purposes. So, funny to see this.

: Stamped Whaler, and Volvo. 90 degree

Now that is a fail. Would that be a closed fail? Which could be catastrophic.
I understand the whaler fails open.
I have to believe this is freeze related and I was lucky to have been replacing everything anyway.

Anyone have a definitive on this one?

Post by **erikv11** » 16 Oct 2014, 15:09

Out of curiosity: drop it in hot water, does it still open?

Post by **Ben850** » 16 Oct 2014, 15:21

erikv11 wrote:Out of curiosity: drop it in hot water, does it still open?

I suppose I could try that Eric, but look at the angle the frame had broken. I would imagine it holding a pressure unnatural to the original design. Logically, it would appear to be in a locked state.

I must fire up the Bunsen burner right quick.

: I will boil it in the name of science anyway, and post results.

Post by **erikv11** » 16 Oct 2014, 15:45

No doubt, it is badly broken and probably broken shut, I am just curious what happens.

Post by **cn90** » 16 Oct 2014, 15:54

We see this all the time in BMW with 80K+ (broken tabs as shown).
Wahler makes very good tstat. I put them in my BMW and Volvo, zero problem at all.
After 80K, I replace them as preventive maintenance and when I remove them, no broken tabs.

For the records, I use strictly Prestone Green (refresh coolant every 3yrs or so) and zero problems during the last 25 years.

Post by **Ben850** » 16 Oct 2014, 17:05

cn90 wrote:We see this all the time in BMW with 80K+ (broken tabs as shown).
Wahler makes very good tstat. I put them in my BMW and Volvo, zero problem at all.
After 80K, I replace them as preventive maintenance and when I remove them, no broken tabs.

For the records, I use strictly Prestone Green (refresh coolant every 3yrs or so) and zero problems during the last 25 years.

Ok, that reaffirms what I've heard of Whaler quality. It was also comforting to see the Volvo logo and date stamps.
Back to my point of failure. It must have happened while immobile. It ran well indicating the 3 o'clock position until I had parked it for a few months.

I'm only curious. It caused me no harm.

Now cn. Which Bimmer won't put me in hock, but give me the driving pleasure of my meager Volvo stable?

Post by **erikv11** » 16 Oct 2014, 18:41

cn90 wrote:We see this all the time in BMW with 80K+ (broken tabs as shown). ...

So do these engines all have warped heads due to the stat not opening and overheating?

joe_pinehill · Post by **joe_pinehill** » 16 Oct 2014, 20:29

I'm paranoid about thermostats. The first New car I bought was a 1984 Mazda 626, when I got out of school. My wife was driving it in '93 and she didnt pay attention to the temp gauge. Thermostat had failed close, car over heated, and the head warped.

Ever since, I have changed thermostats every other time I do a coolant flush. I'll feel really stupid loosing another car because of a $10 part.

Post by **Ben850** » 16 Oct 2014, 21:48

The reason I had even come across that thermostat is that it was in a box with the new one I was installing into the Sedan for this year.
I had driven the '93 n/a sedan the last two winters. It had not let me down but I noticed I could not get substantial heat in the cabin.

It is nice that the OEM whaler thermostats sell for about $12. The temp sensor, which I trust is SWF/Valeo , at $52. respectively but I believe it to be worth what it performs.

: So this is the one in my trusted drivers at this point

I had installed these in the Sedan last week an noticed the ECU immediately paying attention in a positive manor.
I can only imagine the winter heating issues will be done with as well. Throttle response had a noticeable difference.

This was not an endorsement for the supplier, but the only photo of the exact part I could find.

Post by **jreed** » 17 Oct 2014, 04:51

I agree wholeheartedly with the above!
I am having much better results so far with the SWF coolant temperature sensor than I did with the aftermarket "FAE" brand. The FAE developed cracks in the casing and started to read higher temperatures than specification... took some pictures of that failure and posted them here:

https://www.matthewsvolvosite.com/forums ... =1&t=61920

I'm going to stick with the OEM SWF brand from now on.