5-Series (E12,E28, E34, E39, E60)Chat relating to the BMW 5-Series of all generations. Specific models include: BMW 518, BMW 520, BMW 520i, BMW 530i, BMW 528i, BMW 530i, BMW 518i, BMW 524d, BMW 525i, BMW 525e, BMW 528e, BMW 540i, BMW 535i, BMW 520d, BMW 525td, BMW 525d, BMW 530d, BMW 525i/xi, BMW 530i/xi. (BMW 5-Series Forum)
Temp gauge on my 1997 528i with 102,000 miles on it will shoot into the red while at an idle sometimes and if I give the car a couple of good shots on the gas pedal it drops right back down to normal. The car never shows that it is hot while driving and this problem does not happen all the time. Any ideas what might be causing this? Had the radiator replaced last year.TIA.
Originally posted by Torque@Feb 1 2005, 09:38 AM check thermostat, water pump, and fan clutch and check for leaks....
oh and bleed the air from the system if you havent done so....
How high into the red does it get? When you say a couple of shots on the gas pedal, does that mean DRIVING, or reving' while idle. If it goes high enough into the red, you could experience nearly immediate head gasket failure. These ARE aluminum heads. be very careful. I'd get the car into the shop quick unless you know what to look for.
As above : air bubbles, tstat, water pump leaks, etc etc
or it could be a goofy electrical problem, but you really didn't give enough info.
My '97 528i w/ 128K miles is presently doing the same thing. Its been doing it for 4 months. After a new water pump, thermostat, fan clutch, radiator, and exp tank, nothing is fixing it. What's magical is every time a mechanic fixes something, it's fine for a few weeks. But stop-n-go traffic, traffic lights, slow speed driving thru the mall parking lot, etc, is killing me. I can sit at a red light and watch the temp gauge go into the red. But, like you, revving it to 2000 rpm or more will get the gauge to come back down. And at hwy speeds overheating is never an issue, mainly since I have good airflow. Finally the mechanic OVER PRESSURIZED the cooling system and found a small leak in the head gasket. It hasn't been there long based on the amt of antifreeze scum that's built up. But every time a mechanic touchs the car, they top off the coolant. That's why it's fine for 2 weeks. But over time, as antifreeze steams out, the car is less water cooled and more air cooled, making things worse. It's sort of an exponential or snow-balling situation. You don't know it, see it, or smell it, but you are losing coolant when you drive. Both the dealer and an independent charge $2K+ to do the repair. I'm probably going to limp along and add coolant every morning while it's cold. If it gets worse I'll spend the $. But I hesistate since someone told me I could get my oil and coolant to mix, which is a far worse situation. The bottom line is, I've read numerous posts on here about over heating. This forum is great and has helped me tremendously. Everyone says check the obvious, but for me and $1.5K later, the obvious things were not the cause. Good luck, it's frustrating.
I'll put a small wager on a headgasket between the cooling area and combustion chamber. That why you dont smell it or why it doesnt leak. A very minute amount of coolant would be almost undetectable.
mine cost me 2300, because i let mine go for too long. I had to get a new head. These gauges are meant to sit right in the center, anything over to the hot side, you have a problem and it needs immediate attention. I cant stress this enough, take care of it asap.
I would hate for someone to have to refinance their car like I did to pay for a head. while theyre in there go ahead and get a new water pump on, theyre cheap and the mechanic has to remove it anyways.
on a side note, whenever you break open the cooling system, it take a BUNCH of bleeding and rebleeding and rebleeding to get all the air out. when you get done bleed it some more.
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Mine did the exact same things, and it was the fan clutch. It's not an expensive part to replace, nor is it difficult to do it yourself. I spent like $65 on the part and replaced it myself in about 30 minutes. Mine is a 97 528 as well.
The OEM water pumps had plastic impellers and are known to break down over time. If you know for a fact the water pump hasnt been replaced, you can pull it to see if that may be the issue as well. Replacement pumps have metal impellers so they dont have that same issue. You have to pull the fan clutch off to get to the water pump anyway, so might as well check it while you have the clutch off.
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