92 525i excessively cold engine temp on highway - pls help

[jac1d]

Hi Everyone,

I just did a long (4+) hour drive through the mountain passes of British Columbia, and I had a really strange experience with my '92 525i auto.

I noticed during the first hour of the trip that the engine was excessively cool (according to the temperature guage) when I was driving for sustained periods on the highway (this stretch was wide open, flat, valley - not far from Miller Performance in Abbotsford). The guage never got past 1/4 from full cold. I'm used to it being on dead center 5-10 minutes after starting a journey.

I pulled over at the next town and let the car idle outside a gas station for about 10 minutes and the guage crept forward to the center, where I am used to seeing it during mixed city/highway driving during the week.

Thinking that things were ok and perhaps it was just cold on the highway, I headed back out to continue the drive. The temperature needle immedaitely started to fall from the center back towards the cold end of the spectrum. The car ran fine the entire time.

About an hour later I pulled over and checked both of the radiator hoses and these were both warm. The coolant level is fine. The engine was hot to the touch but I would characterize the temperature as normal, not overly warm. There was no sign anything is wrong. No unusual sounds. Defrosting/demisiting working fine.

After that stop I was climbing through mountain passes for the next two hours. Ambient temperatures were just above and just below 0C/32F so it wasn't excessively cold out, just right around freezing. Even during some long uphill sections in the mountains the temperature was still at or below 1/4 on the guage despite the fact that the engine was being taxed (two adults, two kids and luggage in the trunk).

I completed the journey and the car worked flawlessly the entire time, sounds fine, everything looks fine under the hood. But this does not seem normal to me at all.

Any ideas what is happening? I'd welcome all thoughts before I do the trip back through the mountains.

Thanks,

-Jeff

[nmp411]

Almost guaranteed it would be your thermostat. I had a thermostat fail on me and it performed much like yours is.

[mikemxbike4]

Originally Posted by nmp411

Almost guaranteed it would be your thermostat. I had a thermostat fail on me and it performed much like yours is.

+1 Thermostat stuck fully or partially open

[David325e]

Yep, good to see you're still around man. How're the E34s treating you?

And yep, I'd bet good money I don't have its thermo stuck open. I drove 4 hours for winter break last year with my feet wrapped in tshirts because it was so cold. Thermo actually came out in 4 pieces. Good news is one is about $15 and bleeding should be the hardest part of the job.

[jac1d]

Is it safe to drive it home (5 hours) or should I get it done before I leave?

-Jeff

[mikemxbike4]

Originally Posted by jac1d

Is it safe to drive it home (5 hours) or should I get it done before I leave?

-Jeff

Youre ok to drive home

[nmp411]

Originally Posted by jac1d

Is it safe to drive it home (5 hours) or should I get it done before I leave?

-Jeff

Not saying that I do things right, but I drove around like this for about 3-4 weeks before replacing mine and didn't have any problems.
I would assume you would be ok, it just means the engine is staying cooler because the coolant is circulating more.

[David325e]

Yep, drive home is fine. It'll be cold and gas mileage will suffer some, thats all. Mine was likely that way for almost two years before I was somewhere cold enough to used the heat. No worries.

[jac1d]

You guys rock, thanks for that. Treacherous trip through the mountains with snow and ice, last thing I would want is a breakdown. Thanks for setting my mind at ease.

And yes, I'm still around, just been really busy. When I get a chance I need to catch up on things.

Loving both E34s, they've been incredibly reliable daily drivers. I've only had to replace a few bulbs and put snow tires on for the 525i and just snows and a door lock actuator for the 540i.

Whenever we go out we see at least 3-4 of them around, and I also had a chance to visit the BMW wrecker in Burnaby who had at least 7-8 E34s that were largely in tact, plus racks and racks of parts. Picked up two extra basketweaves for the snows...

Anyway, thanks again guys. Will get the thermostat changed out when I get back.

-Jeff

[David325e]

No worries man. We're great than the sum of our parts. I go so tired of recommending your PPI that I just have the link on my clipboard now. And yea just wrap the youngins in some snuggies and roll out.

[Sherman]

Hey Jeff, haven't seen you here for a while. The guys have it; you're running coolant through your rad unregulated. You should be fine to run, even at 1/4, at least it's up a bit. I'd want to make sure you have enough antifreeze in. You wouldn't want a rad channel freezing up.

[zubbie]

Mine has been like that for months. Just putting off the whole coolant system job.