Cooling Troubles

[Kast]

Hi All,

I have a 1988 325i Automatic.

For about 10 years now this car's temp gauge has been running at 1/2 while driving, and goes up close to 3/4 at idle. The car was
in my father's possesion and since it never overheated, he never worried about it. When I aquired the car, I was eager to solve this issue, and being that its a 16 year old car was prepared for
all the maintenance. I used a mechanical gauge in the overflow to verify that when the gauge is at 1/2, the temp is at 180. When the gauge climbs, the temp is around 200. Bmw dealerships keep hinting at the head gasket, but I've never heard of a head gasket that is half blown and doesnt fail for 10 years. As well, the car cools fine at speed. I have changed the Rad, Fan Clutch, Thermostat, Fan Switch. I have not done the Water pump, but the mechanic I used said he looked at it and it
was a metal impeller model so not to worry?? Any one got any ideas?

Thanks.

[Jared at Pelican Parts]

How many miles are on the car? You can indeed have a leaking head gasket that takes some time to finally fail..

If the car is over 100K and has the original water pump, I'd replace it along with the thermostat and timing belt..

[Kast]

Hi Jared,

Thanks for the reply. The car has 110K miles on it and does
have the original water pump, the timing belt and (t-stat were done). Regarding the head gasket, this problem has been around
for literally 10 years, and there is no loss in power and no overheating at speed. Could it still be the gasket?

Much Appreciated,

Kast

[Jared at Pelican Parts]

yep

[jase007]

I have not done the Water pump, but the mechanic I used said he looked at it and it
was a metal impeller model so not to worry??

This is an E36 issue I believe. I have replaced mine at least 2X and there were never plastic impeller pieces, always metal. Make sure you have a mechanic that know E30s.

For about 10 years now this car's temp gauge has been running at 1/2 while driving, and goes up close to 3/4 at idle.

Have YOU bled the system and made sure there wasn't any air in there? E30s love to trap air in the cooling system and can sometimes be a PITA to bleed properly.

You haven't stated if you are losing any coolant? Are you? Also, is there any coolant in the oil? Is the oil a milky brown solution? is there cooland drops (or white sludge) on the oil filler cap underside?

You can have a shop test the oil with a "sniffer" for coolant. That'll help to confirm a leaking (into the combustion chamber) head gasket. How about testing the combustion chambers to see if they hold pressure? (using air pressure). This can also indicate which / where your head gasket might be leaking.

FYI: most all E30 6 cylinders will leak oil down the passenger side of the block from the head gasket / between cylinder #3 and #4.

Good luck and let us know what you / your mechanic finds.

Jason

[makaio]

This may be a shot in the dark, but have you literaly cleaned your radiator? You know remove it, and wash the space out between the fins with water.

When I did this to my car, I noticed a significant drop in water temp.

[Moki]

I have a 1986 325ES with 150k on the clock. I recently installed a performance chip and now it runs strong and loves to rev. However, it started to run hot after about 2 months of chip installation. Now, I can only go about less than 5 miles, the temp. will climb to the red. I have replace the thermostat, timing belt was replaced 30k ago, and I'm not sure if the water pump is original or not.

Questions: How do I bleed the cooling system?
Where should I start looking for cooling problems?

[Kast]

Hi,

Thanks for all the suggestions. I beleive I have done everything
I can think of.....


Radiator
Thermostat
Water Pump
Fan Clutch
Aux Fan switch
Bled by BMW

have all been done in the last 6 months.....but still the
gauge starts climbing as soon as I get to a stop sign.
Most of the time it gets half way between 1/2 and 3/4.
I put a manual gauge in the overflow tank and it seems
to run between 190-205. 190 on the manual gauge corresponds
to just above half way on the dash. Anyone know if this is right?

PS The car is not losing coolant. No Coolant in the oil, no oil in the coolant.

Thanks

[Jared at Pelican Parts]

did you check that the temp sender is working right? My car never goes over 1/4 even in 100 degree weather with the A/C on....

[Kast]

Hi Jared,

I made an interesting discovery today. The temp gauge was sitting up
at 3/4, I turned on the high beams and the gauge down a bit, turned the
fan on high, came down again. More than 1 mechanic has suggested the gauge, and clearly there is something electrical going on.

Thanks.

[Jared at Pelican Parts]

Thats a grounding problem...