Engine runs hotter after skimming head???!!

[seech]

Anyone experienced before?My E34 M50B20 overheated once when one of the hoses tercabut so I had the head (or issit block???) skimmed and a new head gasket put in. Ever since then the running temperature seems to be higher than it used to be. Before, the temp needle was always on the left of the center mark but now when it is hot outside and with the A/C on, the temp is slightly right of the center mark.Its been like this for a while now and no major issues but recently while stuck in a jam, the temp started to move up to the 3/4 mark and only went down after the radiator fan switched to high speed. Even so, the engine really loses power when it is hot. In the early morning or at night power is good (for a pathetic M50B20) and temperature is normal but in afternoon and in a jam it gets hotter and loses power.I read in the New Strait Times CBT that cars which had their heads skimmed tended to run hotter due to increased compression due to the loss of some material from the head/block from the skimming.Has anyone experienced the same thing before? Any solutions? Was thinking whether a thicker head gasket would help but I have no idea how much was removed while skimming so how to measure the gap properly?As a last resort I am seriously considering changing the engine.Pissing me off as I have just spent a small fortune (for me at least) to fix the gearbox up. Now that's perfect and the engine is giving problems. Really Banyak Makan Wang.....Any help or advice would be most appreciated.

 

[antiquer]

no experience with the issue... but i am eager to know as u are. please sifus, advice needed.

 

[fandango]

the cylinder head of my corolla was skimmed by 0.5mm on purpose, to increase the compression ratio. i have not had any problems with overheating whatsoever. the only drawback was that the higher compression wore out the piston rings much faster and created blow-by and higher engine oil consumption.

My guess would be a few possible causes:

1. some blockage of your coolant passages around the block or head due to rust
2. weakened water pump
3. electric fan 2nd speed not kicking in fast enough.
4. clutch fan not working properly

I'd suggest checking the fan clutch first (cheapest), then check the electric fan wiring next. my e34 suffered melted wiring when the 2nd speed kicked in. solved it thanks to a wireman that fitted 3 extra 30amp fuses and also a 85deg water temp sensor from Mercedes.

cheers

 

[seech]

fandango. Clutch fan changed twice. The first time I thought it was not working properly so I changed the still new fan with another new one and found it the same so definitely not the clutch fan. High speed fan using the lower temp switch to operate so it does kick in earlier than stock. Water pump was new as was radiator which I also flushed once before.

Dunno man. A bit frustrating as I would have though I had changed what needed to be changed and still like that. Just exploring the skimming issue as I read about it in CBT so thought might have some merit to it.

 

[affan66]

could be clogged water passage. Check throughout the lines, flush it too. Someone told me you can put this special die in the coolant to check for the flow and pressure.

Have you checked your water pump too? It could be that the water is not flowing fast enough.

 

[astroboy]

Yes... engine will run hotter by common sense with the increased compression ratio. Normally JDM cooling can cope with it, but a bigger radiator is always advisable after a skim, or another common practice is to remove all the thermostat valves in the cooling system. We do that in the JDM allowing coolant to circulate at full velocity immediately without the need of waiting for engine temperature to rise. One more trick for the JDM is to use a higher pressure radiator cap.. allowing the coolant to operate at higher pressure point, thus higher boiling point. But in BMW, this is not an option.. I think..

With the higher compression, the next thing u see will probably be the leaky gasket.. BMW by default is already running higher compression to optimise on performance. There really is no free lunch in this world. Everything we do, has a trade-off/reaction/fruit. God is fair!.. :wink:

As recommended above, u might get away with it by overhauling your cooling system, if u are lucky..

 

[affan66]

when you skimmed the cylinder head, did you change to a thicker gasket?

 

[morpheus5039]

my M20b20 also skimmed b4(done by previous owner as overheating), however, the temperature is normal, highest is 12 o' clock when traffic jam. Changed all hoses and put 50:50 mix of water and BMW blue coolant, relieve the air inside the cooling system through the valve beside the radiator cap. And make sure the Aux fan is running. All run normal after that (My Case)

 

[seech]

Guys, thanks for all the suggestions.

affan, i think normal gasket used after skimming head but not sure. Just wanted to try and confirm if it was indeed caused by the higher compression or is there some other fault. Don't want to spend money to fix a thicker gasket (don't know how thick it needs to be also) and still have the same problem.

Maybe I'll just swap to a M50B25.....

 

[turbology]

Like Morpheus5039 said, have you relieve the air inside the cooling system through the valve beside the radiator cap?

One more thing you should try before you have expensive fix : Redline Water Wetter.
http://www.redlineoil.com/products_coolant.asp
Although some website reviews says it does not make any different, adding it does help for my car. And it don't hurt the car( not like engine additives)

If you can't find Redline WaterWetter, let me know.
Cheers

 

[James Chun]

My E34 also have this problem. when stop at traffic,the temperature needle will shoot to the "red" zone..... engine overheat..... but after drive for a while, the temperature back to centre mark...

my mechanic told me engine kong soon.....so have to change engine...

 

[seech]

Guys thanks for advice. Haven't replied to this thread as my offices internet filter is blocking page 1.

Have definitely cleared all the air in the system. Will give the Redline Water Wetter a try. Does Brother's carry the product?