Engine temp goes DOWN while driving?
 

Yesterday I was driving in fairly cold weather; I'd been going at 55 mph or so for about 15 minutes (so the engine was fully warmed up) and as I started down a hill, the engine temp slowly started dropping. By the time I got to the bottom of the hill, it was down to about halfway between cold and the normal (not quite at the middle) gauge position. The car drove fine; no CEL, stuttering, or anything. The vents continued to pump out warm air.

At the bottom of the hill, I stopped at a light, then drove on a flat road for a mile or so, by which time the temp had started moving back up. It went back to its usual position and stayed there for the rest of the trip (45 minutes or so).

Anyone seen the temp gauge go down like that before? I've never had that happen that dramatically in any car. I'm inclined to not worry unless it happens again. I doubt the dealer would be able to do anything since there was no CEL and I most likely wouldn't be able to duplicate the problem.

Yup, I have noticed the same thing since it has been ass cold here.

Nothing wrong, its just the consequence of having 2 oil coolers and a large radiator pulling out heat.

I am guessing that it needs thermostats on the oil coolers. Does anyone know if it has them?

Gord....
 

I think Gordon from Calgary noticed that with his, last year.
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doc

in this thread https://www.rx8club.com/showthread.p...ight=efficient

I talked about my problem. I have since gone to the same trip and had the same problem. I found that putting the trans in 3rd or 4th to raise the rpm's helped.

Here was the text of that thread:

I was driving home from reno today it was cold this morning, like 38 degrees or so. When I got on the interstate my car was fully warmed up, the needle was in its normal position (just below half way).


Anyway outside of reno you begin to descend for about 45 miles or so. I was driving along and after about 20 minutes I looked at my needle as I was going down the hill and it was almost completely to the left. I turned the heat off the car to help the car warm up.

I noticed when I started climbing elevation the needle would go back to the half way position, but as soon as started going down hill, it would go back to completly cold position again. these hills that I would be going down were like 4 or 5 miles each...btw.

Its ironic..in my rx7 I have to turn the heat on in the summer to keep it from overheating, in my rx8 I have to turn the heat off in the winter to keep the engine warm enough...

One last thing, because everytime I went up a hill the needle returned to normal I dont thing the gauge is bad. I also have never had this problem daily driving in bay area.

any ideas?

thanks.

This happens to me every time I head west on I-70 down the pass from eisenhower tunnel (aprox. 8 miles & 3000ft elevation change) I usually have to put the car in 3rd to keep the gauge up.

This happens to me, but only when when I have about 2 ticks above a 1/4 tank of gas or less. Keeping the RPMs up helps it. However, as soon as I fill up the tank, the problem goes away immediately.

Does this happen when going down hill in gear or are you talking about coasting down the hill in neutral?

This happens while going downhill in gear

I guess we should be thankful that the temp guage moves and depicts a somewhat accurate reading about what is going on with the engine temp.......unlike that retarded oil pressure guage. I saw somebody refer to it on here as a "pretty-looking idiot light"