BMW E36 M43 318I Overheating!

[Faheem]

So seeing as a fair bit of the Z3 was based on the E36 and E30 I thought to myself: what better place to ask this question than on here.

Video LINK:

View: https://youtu.be/F6RgNVt5fZo


I've got a BMW E36 and its been in the family for a very very long time. Unfortunately for the past few years it's had intermittent overheating problems.

The problem started about 3 years ago when one of the coolant hoses came apart during a long journey and caused the anti freeze to splash out in the engine bay which caused some overheating. We pulled over immediately as soon as the engine had started to overheat and we secured the hose on with a rope - just as a temporary solutions for a few hours until we could source a replacement hose. We changed the hose and all was good for a year or so. The engine has since overheated intermittently and there seems to be a severe loss of coolant but I'm not sure where it all goes? There is a very very small leak from the bottom of the expansion tank but it's insignificant and wouldn't cause the engine to overheat as often as it does.

Today we were supposed to go to Birmingham, only about 40 miles away, about 5 miles in the trip the engine overheated with no apparent reason for it to be overheating, after adding water to the expansion tank (we no longer use antifreeze as it simply would not last with the amount we'd have to continually add to the tank) we set off again and had the same problem after another 4 or 5 miles. We stopped and repeated the procedure of adding more water into the expansion tank. The water doesn't seem to be flowing as it should though, it seems like it's getting blocked somewhere and cannot flow. Thermostat has been removed to see if this would remedy the problem but it hasn't. In the end we had to return home as it wasn't safe for us to take the car on the journey. On the return trip it took as an hour to cover 10 miles simply because of how many times we had to stop to let the engine cool down. Luckily the head gasket has not been damaged and the engine itself is still intact.

Any thoughts on what the issue could be?

Watch this video to see what the car does

 

[Antm72]

Have you changed the water pump? It sounds like a flow issue or a severe blockage.
Any sign of sludge on the oil cap or on the dipstick?
I think the waterpump may be worth looking at the older ones have a plastic impeller it may have broken and its just not doing its job.
Looking at your video theres alit of air in there may be air locking somewhere.

 

[the Nefyn cat]

May be worth getting the system pressure tested, gives the chance of seeing where the water's going without having to run the engine and possibly not being able to see what's happening. If you can't see an external leak it must be going inwards (head gasket perhaps).

 

[t-tony]

If it was going internally then it would have to manifest itself by appearing out of the exhaust. Do you get steam from the exhaust or even any drips from joints or drain hole So?

Tony.

 

[Faheem]

Have you changed the water pump? It sounds like a flow issue or a severe blockage.
Any sign of sludge on the oil cap or on the dipstick?
I think the waterpump may be worth looking at the older ones have a plastic impeller it may have broken and its just not doing its job.
Looking at your video theres alit of air in there may be air locking somewhere.

The water pump hasn't been changed for 180000 miles. So there's a very good chance that could be it. I've already had a look to see if the head gasket is bad by looking under the oil filler cap and there doesn't seem to be any sort of sludge or foam or even water mixed with oil in the engine block so I highly doubt the head gasket has gone. Everytime it has overheated the car is immediately turned off and the coolant cap is unscrewed to let all the pressure and steam out. I bought a water pump today so I will be installing that to see if that is causing the problems. Are the water pumps the same on the zeds as well? Might be worth putting the new pump in my Z3 - M44 and placing the old one from Z3 in the E36 (I'll be breaking the e36 in about six months that's why I didn't really want to put a new pump in it) what's the easiest way to check the old water pump to see if it is damaged?

If it was going internally then it would have to manifest itself by appearing out of the exhaust. Do you get steam from the exhaust or even any drips from joints or drain hole So?

Tony.

Nope, nothing at all. Someone told me to jack the car up when bleeding the cooling system is that essential?

 

[t-tony]

jack the car up when bleeding the cooling system

It can help if it's being particularly difficult Faheem, it sounds as though the W/P may be the fault, certainly well worth checking, even if it appears ok I would change it if it's never been documented. A couple of members have had close calls with their water pumps very recently, albeit on the 6 cyl engines.

Tony.

 

[Grumps]

Mine is one of the ones mentioned above. For what it costs I'd change all the ancillaries on the water system. Belts, pulleys, water pump, thermostat impeller etc. I think all the parts were about £150. Well worth it.

 

[Faheem]

It can help if it's being particularly difficult Faheem, it sounds as though the W/P may be the fault, certainly well worth checking, even if it appears ok I would change it if it's never been documented. A couple of members have had close calls with their water pumps very recently, albeit on the 6 cyl engines.

Tony.

Cheers Tony, I've had a look at the water pump today and the calcium deposits had caused it to seize and it took a good few hours to remove it with a lot of patience. The engineers hammer played a big part in the removal. After removing it I came to find the plastic impeller had broken into miniature fragments and it was more or less non existent. I cleaned out the water pump housing with a pressure washer and removed any remaining plastic pieces from inside, fitted the new pump, gave the radiator a very gentle clean and used very light pressure in all the hoses to clear any blockages. Will be bleeding it later on today and hopefully that fixes it.

Mine is one of the ones mentioned above. For what it costs I'd change all the ancillaries on the water system. Belts, pulleys, water pump, thermostat impeller etc. I think all the parts were about £150. Well worth it.

If it were my zed I'd spend £150 but this e36 is so old, the lacquer came off the bonnet, the seats tore and the door cards bubbled. It was the first car I ever crashed - I was 15 when I did and I damaged the o.s. Wing quite badly. The car probably won't even fetch a £150 if I sell it so it's not worth for me at this time investing that money into the car. Also the clutch is slipping - still going on the factory clutch after 180k miles lol. I'm considering restoring it as besides from the clutch and the Overheating issue mechanically it is great. If I do I'll post some pictures of the car once it's done.

 

[Faheem]

Mine is one of the ones mentioned above. For what it costs I'd change all the ancillaries on the water system. Belts, pulleys, water pump, thermostat impeller etc. I think all the parts were about £150. Well worth it.

Here is the MOT Failure list

 

[t-tony]

Hi Faheem, lambda failure is most likely down to the major leak of exhaust gases at the rear end. New exhaust most likely would cure three fail items.

Tony.

 

[Faheem]

Hi Faheem, lambda failure is most likely down to the raj or leak of exhaust gases at the rear end. New exhaust most likely would cure three fail items.

Tony.

Hi Tony, thanks for the reply. What is the raj? The exhaust was actually sealed with some sort of a sealant to make it pass the MOT. Lambda sensor wouldn't be responsible for the Overheating would it?

 

[t-tony]

HI mate edited the post , should have said major leak of exhaust gases. A blow at the rear of an exhaust system has a big influence of the lambda reading.

Tony.

 

[Faheem]

@t-tony guess what, I replaced the water pump which looked to be broken and beyond repair but the problem is there I'm honestly our of ideas. There is a very small drip coming from under the expansion tank but I don't think that could cause so much overheating so quickly. I'm now suspecting the fan clutch, the fan itself or the radiator.

 

[t-tony]

Is the water circulating through the whole system including the heater? If it's not there is still an air lock in there somewhere. Have you had the bleed screw on the expansion tank open while running the engine?

Tony.

 

[Faheem]

Is the water circulating through the whole system including the heater? If it's not there is still an air lock in there somewhere. Have you had the bleed screw on the expansion tank open while running the engine?

Tony.

No the water doesn't flow at all. I've had the screw open squeezed the tube while the screw was off and even kept the engine running. Air lock isn't going I checked the radiator and all the hoses within it and pushed water through each one of them and it seems to be allowing water to pass freely. If the gasket was gone would there definitely be a sludge under the oil cap? There is a noise which sounds like the water is blocked. Almost sounds like a blocked toilet.

 

[t-tony]

Do you have capability to use a garden hose and back flush the whole system through, it would involve disconnecting at lot of hoses but would eliminate potential blockages.

Tony

 

[Grumps]

No the water doesn't flow at all. I've had the screw open squeezed the tube while the screw was off and even kept the engine running. Air lock isn't going I checked the radiator and all the hoses within it and pushed water through each one of them and it seems to be allowing water to pass freely. If the gasket was gone would there definitely be a sludge under the oil cap? There is a noise which sounds like the water is blocked. Almost sounds like a blocked toilet.

You wouldn't always have sludge if the head gasket has gone. Would depend where the gasket has failed. Could be oil to water no the other way round. Had anyone mentioned thermostats? I don't have much knowledge, just trying to throw ideas in. I await the deluse of "what the hell you going on about grumps!!!!" Lol!!!

 

[Faheem]

@Grumpy what the hell are you going on about. kidding. Yes we've removed the thermostat completely as we thought that if the water flows all the time then it may help keep the engine at a cooler temp. No luck though.

@t-tony I'll give that a go although I don't have any idea of how to perform it as I've never done it before. One thing that left me curious is that when I removed the water pump there was absolutely no coolant in the housing which was very strange. I've seen multiple people changing their water pumps and in every case there is always a bit of coolant that spills out from the housing when removing the water pump. I wonder whether the radiator on a z3 and that on an m43 are the same. Would be worth swapping and checking if they are.

 

[Jack Ratt]

There might be a bit of the plastic impeller blocking the flow somewhere may be ?

 

[Grumps]

I now yes the impeller! Mine obliterated in April during the Derbyshire cruise, I'd check that it's all in tact!