97 528i (e39) overheating?????

[BALKAN]

this is the second time its happened and its the oddest thing. i drive this car back and forth to work. the water gage goes into red (lights up), no check engine light, and within 10 sec. its back to norm. this happens within 10 miles of driving back from work, almost to the same exact mile marker. i pull over, pop to hook and check overfill bottle, which is at normal level, no excesive heat.

my question is, could it be sensor problem? the car has 103k, and i've owned the car since 79k. the only maint. has been oil and filter change. i know its due for a good tune, flush and all. i did replace front brakes, disks and sensor (easy).

i need some recommendations, what to beware of, and common problems with this model. i love the car and would love to keep it as long as possible, well maybe until i find a nice 540 6spd. http://www.bimmerwerkz.com/forum/ima...ons/icon10.gif
Talking

[cnn]

Originally Posted by BALKAN

this is the second time its happened and its the oddest thing. i drive this car back and forth to work. the water gage goes into red (lights up), no check engine light, and within 10 sec. its back to norm. this happens within 10 miles of driving back from work, almost to the same exact mile marker. i pull over, pop to hook and check overfill bottle, which is at normal level, no excesive heat.

my question is, could it be sensor problem? the car has 103k, and i've owned the car since 79k. the only maint. has been oil and filter change. i know its due for a good tune, flush and all. i did replace front brakes, disks and sensor (easy).

i need some recommendations, what to beware of, and common problems with this model. i love the car and would love to keep it as long as possible, well maybe until i find a nice 540 6spd. http://www.bimmerwerkz.com/forum/ima...ons/icon10.gif
Talking

1. I'd start with a COOLING SYTEM overhaul. The 6-cylinder engine cannot handle overheat very well, resulting in a cracked cylinder head....a very expensive problem.

I wrote this COOLING Tips and Tricks for the E39:
ENTIRE COOLING SYSTEM REPLACEMENT Tips and Tricks (Very Long, Enjoy!)

About $550 for parts. Labor is DIY.

2. Once the COOLING SYTEM overhaul is done, the problem should not recur. Otherwise it could be the symptom of cracked cylinder head.

cnn
98 528i 5sp 93K

[superdeadman]

yup cooling system.
Sounds like you might have a problem with a thermostat, though i don't know how come it only happens at certain place

[fastshivy]

Could be many things. I would try to get an infra red thermometer and see what the actual temp of the coolant is. Does the electric fan come on? Are the belts tight? Most likely the radiator is a little gunked up, but you must first make sure it is getting hot and is not a false reading.A false reading could be in the gauge or the sending unit. You can also check the head gasket for exhaust leaks by purchasing a tester. Napa and others sell these and you simply mix a solution in a glass cylinder and hold it in the radiator neck or coolant reservoir and look for a color change. This is something you need to solve quickly, esp with an inline 6 cylinder. The heads on these cars are very long and can warp easily.You just start eliminating things starting with the easiest. Good luck and keep us posted.

[BALKAN]

thank you all for the replies.
last night i topped off the antifreeze, it was low, it took a bit over a qrt. i checked for leaks, stains and odor. nothing.
i really dont think that the engine is overheating, due to the fact that i had my hand on top of the intake cover while the gage was in the red (on highway). also the overflow tube was not full, i did open the overflow cap slightly and water didnt gush out. fans were running, check engine light didnt come on.
the gage was moving up and down too quickly to justifie a true engine overheating. from going to the red and returing to norm temps was happing with in 10sec.
anyways, i drove the car today 50miles and not a single problem, the temp. gage remained at normal reading. i made an appointment with local shop to inspect temp sensor unit and gage. also ill have him do a pressure test on cooling system after a good flush.

one thing i like to mention is that early this month i installed full synthetic oil, instead of synthetic mix blend. i have heard that the temp may vary at initial change over. is this true?
is it a good idea (or worth it) to have the engine oil tested for foreign material?
once again i appreciate everyones help and ideas.

[fastshivy]

Congratulations, it sounds like you are on the right track.
I can't imagine synthetic oil would alter the temperature as it is not connected to the cooling system.The one exception would be the oil cooler, but the entire system is controlled by the thermostat. If anything I would expect it to drop. Synthetic oils are wonderful and IMO worth the money. My 540i had a clatter and small knock sometimes when starting it up; It would then go away quickly. I was using Mobile synthetic. I went to red line synthetic and it is absolutely quiet now. I use synthetics in my Tahoe and it keeps that famous lifter clatter Chevys are known for quiet. Synthetics seem to stick to the parts better giving better lubrication and a less dry start up....just my opinion. I am getting old and any teenager will disagree me, because old people don't know anything! You see we have the files in our brains, but we can't find them. It is kinda like your hard drive getting full, and your processor slowing down.
Testing the oil seems a bit extravagant, unless you are having oil pressure or knocking problems.

[superdeadman]

the only problem with using synthetic oil after using normal one on engines with high mileage is leaking.
If there are no leaks, synthetic is definitely the best choice, without a doubt. And you're absolutely right fastshivy - i synthetic oils stick to parts FAR BETTER than regular oil. your engine will run MUCH MUCH longer and better with synthetic oil rather than with regular one

[BALKAN]

once again thanks.
the car is doing great (knock on wood), no problems what so ever. i did have to add a small amount of antifreeze today. have no leaks, smell, or any smoke coming out the exhust. oil is clear ( not filmy when you have gasket leaking).
ill stay with full synthetic from now on. the wife had me using blend being inexpensive, but in the long run its cheaper. ill run my full synt. 5k miles before an oil change (its safe i asume).
i have noticed the car at start up (cold) makes a deep toned exhust sound, like a race car. this only lasts until idle drop apprx 1min. my mustang did the samething only it had an aftermarket exhust. is this normal or does the muffler need changed? if so, what brand is ideal.

fastshivy sounds like you need a young clerk to organize your files.