strange overheating problem

[tigalima]

i have an overheating problem with my car..
well, i've changed some parts to overcome this problem but it still overheating..

parts that i've changed:
-radiator
-viscous van
-waterpump

any sugestion??
thnx for your attention

[march109]

Other than overheaing what are the symtoms?

is it soon after start up, after a few miles? when driving, when parked both ect ect????? What does the temp needle gauge do? are the hoses hot under the bonnet? is the heater giving hot air?

What engine?

[tigalima]

btw my engine is m40 (318i),,
it's overheating when i'm driving after long distance (inter-city)

the heater is fine, it's not giving hot air
well, i've never checked the hoses from the radiator,(next time i'll check it out)
the needle gauge it's a little bit strange ,it's moving around, sometimes in the middle bar and back again to the second bar,, after that it will go to the last bar (red zone) after i drive in some period of time (like 2 hours)...

could it be the thermostat???

[march109]

the heater is fine, it's not giving hot air

If its fine and the needle indicates the coolant is warm (ie above the blue mark) the heater should be able to blow warm if not hot air!

Does it?

[tigalima]

uhmm
sorry i forgot to tell,,
i lived in a tropical country, and we don't need hot air from the heater CMIIW
so i think the "hot air" feature is not included to my car

btw what is the connection between heater and overheating??
sorry i lack of knowledge about engine system

[dMh]

right, I really seriously think its the thermostat dude... you NEED to go to a garage and have a look at it...

[march109]

Sort that avatar, its too big.

The heater not giving hot air normally indicates an air lock in the cooling system which can cause the symptoms you describe but since you can't get hot air from your car anyway its not as easy a test as for us here in the UK.

I don't believe in just swapping out parts for the sake of it. So flush your cooling system and bleed it properly before you spend any more money, test the thermostat by removing it and dropping it in some boiling water and you should be able to see it open. If this doesn't solve it you could have a more expensive issue and all the parts you have swapped out allready will just be money down the drain.

[spp320i]

Hi, regardless of where you live, the heater should give hot air - whether you need it or not, it's included!

The connection is that the heater being able to blow hot air shows that there aren't any airlocks in the cooling system.

If the heater won't blow hot, then that means there's probably an air lock in the cooling system, and that can crack the head - leading to expensive repairs.

There's lots of posts about how to bleed the cooling system properly - get this done ASAP just to clear out any airlocks there might be.

Once bled, if the same still happens, then it could be a thermostat that's being temperamental, or it could also be that you have a faulty viscous coupling. Have you tried the newspaper test to see if the viscous is working properly?

Hope that helps!

[tigalima]

well, thnx to all of you for the reply..

well actually i don't know exactly about the heater things,, it's a second hand car,
maybe the owner before me got it changed?? my mistake if i said that is not included lol

okay i will test the thermostat,,

btw how do i know if the viscous coupling is working properly with a newspaper test.. can you explain it to me???

thnx

[dMh]

@SPP320i

what Tigalima means is that here In Indonesia most E30's have their temperature switch disabled by previous owners who in an act of idiocy or plain ignorance think that the dial has no use since we live in the tropics, but really man, we do get cold in the more mountainous regions here, especially during rain season... it's quite rare to find a properly working E30 in respect to the electrical/VAC system.

but what do you mean by the "newspaper" test... I haven't heard it before

[march109]

but what do you mean by the "newspaper" test... I haven't heard it before

Only works on vehicles with a viscous coupling driving the fan, since the fan will spin all the time but is only properly 'driven' when the engine is warm the best way to test it withough loosing a finger is to insert a rolled up newspaper, if the fan shreds the newspaper it is being 'driven' and is on orengaged however you like to describe it. It should be on if the engine is warm or hot so whenthe temp is upto 3/4 do the newspaper test to check the viscous coupling is working.

[spp320i]

DMH - thanks for the explanation, I've learnt something new today!

here In Indonesia most E30's have their temperature switch disabled by previous owners who in an act of idiocy or plain ignorance think that the dial has no use since we live in the tropics

That does seem a bit daft, and a bit dangerous as it would be hard to know if the cooling system has been bled properly without having the option of having heat coming out.

The newspaper test is as March109 describes it - at low temp a newspaper will stop the fan, but once the engine temp's up to about half, the fan should be driven by the viscous clutch, so a newspaper will be shredded if the viscous works properly.

Let us know what you find - I take it there's no signs of oil and water mixing are there?

[tigalima]

hmmm
i think i understand how the newspaper works i'll try it later..

as i know, there is no oil and water mixing, but! sometimes there is a white smoke comes out from the exhaust system (muffler),

what do you think?

[dMh]

what? white smoke!!!!!????

well i don't plan to upset you or scare you or anything, but i do think it could be your piston rings have been fried, which causes lost compression on the combustion chamber, that's whats causing the smoke. which means you need to get new piston rings = engine overhaul. yikes!

CMIIW

[march109]

As long as it is smoke and not steam, a fair bit of steam on an m20 is normal.

[dMh]

well he doesn't have an M20, he has an M40

but anyway, why does steam on an M20 normal?

[march109]

Oh yeah, couldn't be arsed to read the thread again.

M20's just steam ALOT. its common plenty of threads on it, something to do with the ammount of water in fuel anyway. Steam dissipates in the air quickley though, where as smoke doesn't.

[dMh]

oh i see, well.. that's new to me.

not much M20 buzzing around here anyways

[Brianmoooore]

White smoke IS steam (or water vapour to be exact, as steam is invisible). All internal combustion engines emit water vapour as large quantities of it are produced as a normal product of combustion. Whether you can see it or not depends on how much the steam cools inside the exhaust system, and on the weather conditions.
Blue (oil) smoke and black (excess fuel) smoke are the ones you should worry about, although excess white smoke (coupled with a loss of coolant) will indicate a leak from the cooling system into the inlet or exhaust tracts, or the combustion chamber. The latter will also normally also result in coolant being blown out of the system through the pressure cap as well.

[tigalima]

@brianmoore

well, you're right, that is exactly what happened to me!!

the coolant being blown out of the system through the pressure cap...

so maybe there is a leak in my engine??

what should i do ???

[BreadBin]

A compression test would help - it sounds like either the headgasket has failed or the head itself is cracked

[dMh]

Yikes!

man i hope its not a cracked head...