engine heating once again

10 days ago my car started heating up in slow traffic, I just though aux fan issues since the heat sensor on the radiator was not triggering the high speed, today I removed the hole cooling system, cleaned the radiator fins and it was a chance to replace the spark plugs, belts and visco clutch, I also removed the thermostat to check if the system is cooling fine.

I ran the car with AC on, aux fan worked fine, but it overheated within 20min, if I hit the accelerator to make the fan cool the radiator, it cools back to the middle.

I would have 2 doubts, either the radiator has some blocked areas, or bad head gasket.

what are your recommendations guys?

Quote:

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Originally Posted by grave77

10 days ago my car started heating up in slow traffic, I just though aux fan issues since the heat sensor on the radiator was not triggering the high speed, today I removed the hole cooling system, cleaned the radiator fins and it was a chance to replace the spark plugs, belts and visco clutch, I also removed the thermostat to check if the system is cooling fine.

I ran the car with AC on, aux fan worked fine, but it overheated within 20min, if I hit the accelerator to make the fan cool the radiator, it cools back to the middle.

I would have 2 doubts, either the radiator has some blocked areas, or bad head gasket.

what are your recommendations guys?

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HGasket is my bet...:(

Any coolant loss? If not, not the headgasket.

You can check the radiator. Maybe that is blocked. There are non contact thermometers which you can direct on every spot from a distance to check the temperature.

Check the fan clutch, on my website (scroll down) there is a link to MWrench E32 site, under white paper there is the best fan clutch test I know.

I have been observing the car lately and here they are:

When I fill the car with water it takes time to sink in as if there is something blocking the way.

I have blocked the heater pipes as we dont need it here and its causing in efficency of the AC. but I was wondering if this would complete the water flow at the end of the engine?!

as long as the car is moving the car wont heat up, the clutch is working aslong as the car is not overheating, once it overheats the clutch seems to stop working. so I will replace it, but if the radiator is blocked I guess the clutch wont function propperly too.

there is slight water loss, but after the car was overheated, maybe its the cap releasing pressure or I was thinking if the water pump is leaking from the back where the pipes has a rubber O-ring.

Questions:

would an old Catalytic converter cause overheating like that? if yes how would the engine behave?

how can I know that the water pump is functional, note that I'm not using the thermostat and the water is flowing all the time regardless of the engine temperature.

last week I have replaced 2 exploded hoses due to overheating, when I park the car and the car was a little overheated, the water temp increases when the engine stops and it blew up the small hose on the top of the water pmup first, after 2 weeks ( yesterday ) it blew up the hose going from the engine to the heater core. ( that was pain to replace !!! )

this is a full report untill yesterday, final observation was that I found alot of calcume build up on the pipes, if I pour in a small glass of vinigar and run the engine for few min then drain that out, would it help cleaning it?

Thanks guys, can't survive without your help :)

When I fill the car with water it takes time to sink in as if there is something blocking the way. Possibly normal

I have blocked the heater pipes as we dont need it here and its causing in efficency of the AC. but I was wondering if this would complete the water flow at the end of the engine?! I think the water needs to circulate through the valves byt not the heater core to complete its path

as long as the car is moving the car wont heat up, the clutch is working aslong as the car is not overheating, once it overheats the clutch seems to stop working. so I will replace it, but if the radiator is blocked I guess the clutch wont function propperly too. Replace the clutch first then Radiator if other remedies do not work, cheap fix

there is slight water loss, but after the car was overheated, maybe its the cap releasing pressure or I was thinking if the water pump is leaking from the back where the pipes has a rubber O-ring. Releasing pressure is the goal of a good cal, exploding hoses means the cap is bad

Questions:

would an old Catalytic converter cause overheating like that? if yes how would the engine behave? Big loss of power, will seem like you have NO power and it will most likely stink of sulpher in the exhause. If very clogged it is possible for the engine not to start.

how can I know that the water pump is functional, note that I'm not using the thermostat and the water is flowing all the time regardless of the engine temperature. No thermostat is bad, the first cylinders encountering cold water will wear just as a comd cylinder would wear in a vey cold climate much much faster than in a warm climate with a thermostat.

last week I have replaced 2 exploded hoses due to overheating, when I park the car and the car was a little overheated, the water temp increases when the engine stops and it blew up the small hose on the top of the water pmup first, after 2 weeks ( yesterday ) it blew up the hose going from the engine to the heater core. ( that was pain to replace !!! ) Need a new expansion tank cap!!

this is a full report untill yesterday, final observation was that I found alot of calcume build up on the pipes, if I pour in a small glass of vinigar and run the engine for few min then drain that out, would it help cleaning it? Try a HUGE bucket of vinegar, but heed that the vinegar will also have the tendancy to eat aluminum over time. There is better war=ys to get the calcium buildup out. A new radiator is a much better choise than introducing an acid into an aluminum engine.

Thats my guess and I'm sticking with it.

well...I replaced the cap, removed the radiator and tookit to a cleaning shop, still the car is heating up especially when I throttle it on the road, I cannot seem to see the water circulating, I will put back the thermostat but I removed it to see if the water flow is normal. untill now all what it shows it head gasket.

Thanks bro.

Removing a thermostat completely is not a good idea on a BMW. The T-stat also acts like a kind of 2-way valve. If that is not there, then the coolant will just take the way of lowest resistance.

then the way of lowest resistance is the way out of the engine, and this will make things wors, right?

I think it is faulty water pump, sometimes it causes weird overheating.

seems I will get a new thermostat and a water pump. hope things will work now !! thnx

I'd suggest a thermostat with 75 C Spring.

A thermostat with 75 C spring does not help much. What is does: it opens a bit earlier when a cold engine is started and comes up to operating temperature. The normal operating temperature of the M70 engine is anyway >75 C, so any available thermostat for the M70 is fully open anyway when operating temperature is reached.

I will restore back the 85C therm. today I ran the engine to fill the battery again since it was off for 2 weeks. I started to suspect that blocking the heater pipes is playing a big role in stopping the circulation in addition to the t-stat removal. I attached the realoem graph of the water cooling system. I blocked the hose with the circle around and the inputs of the heater core pipes. actually this is where it keeps exploding and popping out when it heats. hope this can get me somewhere closer to whats going wrong. http://www.bimmernut.com/forum/attac...1&d=1213295198

Ok, unblock the heater pipes & examine it, some times it causes overheating issues, perhaps it has made some resistance in the water circuit leading to high pressure.

I'd suggest one more thing, check all the hose clamps precisely & also check the thermostat cover & gasket. some time faulty clamps wont leak water until it reaches operating temperature.

Are you Bleeding all the air out of the system? Very important with these cars, Can you stop the fan with a Newspaper? If so bad fan clutch.

connect the 2 hoses together instead of blocking them.

latest updates:
connected the 2 hoses, water seems to flow better, I also replaced the water pump as the pump was a little loose and I wanted to make sure all the cooling system is working again, I also restored the 81C t-stat. while installing the pump I put the radiator on the floor and filled it with a cleanning fluid contains Acid, as the radiator was contaminated with calcium build ups.

I installed everything back and after 25min the engine heated up again reached 75% of the gauge.

then the input hose to the pump exploded, it was a little old, but I didnt expect to explode.

now as it seems that the engine head gaskets are blown, but if I wana change them I cannot do it in my home garage or what I mean to say is that its better to get the engine out, right?

I'm tending to install an M73 engine with its DME.

any advice here, the car been parking for 2 monthes.

taking to car to a mechanic to fix the heads will cost the same price of a good second hand engine.

Thanks alot guys I know I was a headache in this case. :)

If you really want to change the engine, stick with the M70. Too much work for you to change, check if fit etc.
engine wire loom, ECU's, EML, does the transmission bell housing fit etc.

And before you change the engine, find a good shop which can test the old engine if really the headgaskets are blown. Pressure test, and so on.

well I was thinking last night, and I wanted to throw my last card, I will take out the radiator to check it up if it still have blocked lines.

how possible would it be to have some blocked water lines in the head or the block? does such a thing happen?

forgot to write that when the car is moving the heat starts to drop but it seems to be slower than before.

is the pressure test using the meter on the spark plugs?

Thanks again :)

well I was thinking last night, and I wanted to throw my last card, I will take out the radiator to check it up if it still have blocked lines.
how possible would it be to have some blocked water lines in the head or the block? does such a thing happen?

Never say never, but I doubt it

forgot to write that when the car is moving the heat starts to drop but it seems to be slower than before.

That basically points to a bad visco clutch.

is the pressure test using the meter on the spark plugs?
yes, see here, very simple stuffhttp://www.amazon.com/Actron-CP7828-.../dp/B00020BM28
http://www.justoffbase.co.uk/Compression-Testers

I have one of those testers, I have to bear the pain of testing it :S as changing the plugs was one hell of a job with the lack of space.

visco clutch is working fine without any doubts I did the news paper test, I aslo installed a new clutch when I installed the new pump.

I will do the compression test. but what will show me for sure that there is a leak?

how long should it hold the compression on the gauge?

Thanks

Just got my car a week ago, replaced the engine with a second hand clean dry engine, runs cool now, the old engine had a blown gasket, the labor cost for replacing the gasket is more expensive than a second hand engine. more over the pressure was low before.
I have discovered why the previous engine blew its gasket too, the AC condencer is blocking the air from cooling the radiator, more over the radiator is an aftermarket too. Visco clutch is an after market too as the original is very expensive, so it works fine at normal temarature conditions but when it starts to get warmer seems that the after market visco clutch doesn't work efficiently like the original.
one funny thing happened is that the car may warm up on idle in the night more than the day but if I turn off the AC the card cools down again, I can also notice the air pressure from the aux fan is returning back more than flowing into the radiator. so now I'm considering replacing the condencer with a newer version and if possible those with wider fins to allow the wind to flow through.
any advice I can get about this?

Cheers :)

usually the condensers get a bit oily and clog with dirt. If you can pull the radiator spray the condenser with degreasing stuff and hose the thing out from the engine side. Same thing with the radiator. The clutch must be 100% especially in the heat where you are. Does the suxillary fan turn on with the ac? Does it turn on with the AC off when the engine gets hot?

well been experimenting with Visco clutches in the past week, most of the after market Visco clutches plays games, the worst were KM auto technik and Trucktec, they didnt last for more than weeks to start leaking oil or not working at high temp.
in my case I installed an original second hand one before I decide whats going wrong, its better somehow, still I can see that the AC is heating up the condencer to make the cooling less efficient. Aux fan works at both low speed and high, turns off with the AC off unless the fan was on high speed, then it stays on untill engine cools a little.
some people recommended the 740 or 540 clutch, others were recommending the E34 535i aux fan, I will keep on looking to see whats going wrong, but wanted to ask you, have you driven ur car over 140 or 150?

cheers

Quote:

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Originally Posted by grave77

have you driven ur car over 140 or 150?

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No, jetted up to 135 and back down a couple times. Car gets there fast like a bike. No need to cruise at that speed on these roads, just not designed for it, curves not banked and straights without hills are few and far between.

Not sure about swapping clutches from other engines, did you run the part number on realoem to compare?

I didn't really check that, when I was at the scrapyard I was looking for those with 3 screws for mounting the fan and a big nut. thought about it, but been busy trying them on. i'll check that soon
thanks :)

You have a LOT of choices here.

Part Cross-reference
Part 11527502804 (FAN COUPLING) was found on the following vehicles:

E31: Details on E31
E31 840Ci COUPE
E31 840i COUPE
E31 850Ci COUPE
E31 850CSi COUPE

E32: Details on E32
E32 740i SEDAN
E32 740iL SEDAN
E32 750iL SEDAN

E34: Details on E34
E34 530i TOURING
E34 530i SEDAN
E34 540i SEDAN

E38: Details on E38
E38 740i SEDAN
E38 740iL SEDAN
E38 740iLP SEDAN
E38 750iL SEDAN

E39: Details on E39
E39 540i TOURING
E39 540i SEDAN
E39 540iP SEDAN

interesting, mine is ripped off an E39 530 double vanos, but I have noticed that the behaviour of the clutch on the 540 and 750 E39 and E38 is a little different than those on the smaller engine cars. I'll dig to get one off of those cars are the original is not available in the market !!

all should work fine as long as the blades have the same amount. The cooling ability is the same, when hot works harder, thats about it dude.

Quote:

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Originally Posted by grave77

interesting, mine is ripped off an E39 530 double vanos, but I have noticed that the behaviour of the clutch on the 540 and 750 E39 and E38 is a little different than those on the smaller engine cars. I'll dig to get one off of those cars are the original is not available in the market !!

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well recently its working better, but seems its not working at all untill the radiator is hot, usually the clutch should go on when u start the engine then goes off. but this one doesn't otherwise its ok. the Aux fan is blowing fueses so it seems to have few coils drawing more current. that means its spinning slower than its supposed to be. I have bypassed the fues to keep it on. but sometimes I find that wire toasted.
one good change happened is that when I turn off the engine for few minutes and return back to drive I don't find the temp in the high zone. before it was going high.

I'll keep observing
Thanks dude ...

You didn't mention the year or engine of your car, but I have heard that the e39 model (3-series, ~1992 thru 1998) used a plastic impeller in the factory water pump -- and the impeller would eventually fail due to age or temperature, and basically stop pumping water that would cause over heating.