SC Running Hot possible fix?

iaragon

Registered User
This sounds bizarre, but if its not, please explain to me. I've been dealing with my temp gauge pushing the hot-side. The gauge passes the "M" in NORM and gets hot enough for the idiot light "check gage" to turn on. I've replaced the sender sensor, the temp sensor and gauge, didn't fix it! The radiator is less than a year old (less than 10k miles) with no leaks nor trapped air.

This past weekend I changed my battery because I had added an amp, cd player, woofer, and more powerful speakers some time ago. Anyway, the battery was 3 years old and cranking slowly for the last 3-4 months so I replaced it with one with more CCA's (don't remember right now)

Well, ever since, the temp gauge is behaving! no "check gage" light and needle is staying below the "M" in NORM running cooler (according to the stock gauge).

make sense??? :confused:
 
How old is your radiator cap?

Does it get hot all the time or only when you are sitting for long periods of time or in heavy traffic? Is your fan coming on?
 
I agree with Kevin,

Just did my radiator, hoses, clamps, tstat, water pump, etc. Did not do the cap because after all what can go wrong with a cheesy little cap? Anyway, when it gave up all 16 lbs of fury the car starting filling up the overflow, then "overflowed", then started running hot. I swapped it out and now my temp gauge shows 200 at idle in traffic, and the stock analog gauge (i.e. the worthless thing on the left side) reads at the M in NORM at 200/205. I think the fan kicks on at around 210/215.

Don't know what the heck a battery would have to do with a gauge (unless this is a eurotrash (BMW) forum). :)

M
 
I have the same problem with the car getting hot. Maybe ill go pickup a new battery and see if that fixes it :p

Realistically, ill probably get a new cap on my next trip to the parts strore.

-Nick
 
Low battery voltage, and/or weak battery made my '89 read incorrect since the gauges run off (I think) a 5v voltage regulater in the dash if memory serves.

Had a similar problem when the alternator was dying on my '89.

I run a mechanical gauge on my '91 with a 165 degree thermostat. Generally runs at about 165 to 170 degrees, with the stock gauge showing less than 1/2 scale (don't remember what letter).

I believe the fan comes on low speed at around 220 degrees, and the high speed somewhere just before 230 degrees according to the manual I have and experience gained before I solved my "running hot" problem (bad AC compressor coupled with a 195 degree thermostat).

Before everyone tells me I shouldn't run the 165 degree thermostat because I'll be stuck in open loop and suffer bad fuel mileage, it turns out I went from about 17mpg before, to routinely 22 mpg all the time now. Runs better and somehow gets better mileage in my case.

I'd get the cap checked at Autozone, or just replace it for insurance as it's a cheap item anyway.

Hope this helps
Bill
 
I know... but, its all better now...

Radiator cap is brand new. Believe me, I think its odd/bizarre too, but I did all the common sense things:
  • new radiator
  • new cap
  • new fluid
  • no leaks
  • air out of system

Yes, fan operational. I bought a infrared gun to measure temp at time of fan spinning. Gun read between 210 and 220 when fan powered up, which by other's stories, is normal for stock t-stat in stock engine. The gauge would creep up when car under load (uphill) or stopped in traffic.
 
wire switch in

I purchased mine from a fella that wired the fan to a switch and you can turn it on and off as you wish.
 
if the top hose gets hot

then the water pumps works right? or am i wrong, i know that also means that the tstat opens up, and lets coolant flow. im getting a 165 and checking this out for myself. if no good, a good 180 should do.
 
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