Funny cooling problems

[Rompsku]

Hi Guys

EDIT: I'm driving a '96 328i with about 340,000km. Let me know if you need any other info on car.

I'm still having issues with my cooling system. I have replaced the viscous fan which has made things a lot better, but I still feel like there is problems with the cooling.

What would the symptoms of a broken thermostat be? My temp gauge always sits perfectly in the middle (a bit to the left when doing high cruising speed on the highway). Even when driven hard or sitting in traffic, she stays perfectly in the middle, however, popping the hood after a hard drive, and everything under there is extremely hot. I can barely touch the expansion tank.

Also, there is a "woosh" sound coming from the intake side of the engine. Can only hear it at idle and it's barely audible, but definitely there. Could that be a headgasket leak? I have no other signs of head gasket issues... just a little white smoke at startup and when revving really hard.

I'm think I should just replace the entire cooling system as these are prone to issues apparently. Can I get a rough estimate on cost for parts to replace everything related to the engine cooling?

Finally, I heard a weird knocking sound coming from the engine. Happened at idle and only for about 20 seconds. Was a random sound, not rhythmic or linked to the rpm. Just a audible "kadoof" and a slight jerk/vibration could be felt from inside the cabin. Turned the car off and on again and the knock was gone. Any ideas? Sounded like it was coming from the back of the engine.

Edited #2: Thought I should add, fuel consumption is still pretty good. About 10-12 in town, < 9 on the highway.

Thanks for all and any input.
:ty:

PS. I'm in Mitchells Plain, Cape Town, if any members in the area, let me know!

 

[pi328]

It would help if you tell us what you drive, ie. E36, E46, etc ?

 

[Rompsku]

:fencelook:
Edited my post. It's a '96 328i.

 

[pi328]

In my opinion, don't just blindly replace bits that don't need replacing. I've had the viscous fan problem. Mine was related to the viscous fan clutch that leaked, coupled with a fuse that went. Car only overheated when sitting in traffic though. My temperature needle only moved away from the middle when there was real trouble, never ever under any other circumstances. Start with the basics. How hot it is really getting? If it's a "new" car, you might not know what normal is, so ask a buddy with a similar car. Do you lose water in your cooling filler bottle? And yes, it will be hot after you've driven the car, so wait for the car to cool down before you open it. If you lose water, it could be radiator or hoses or some other leak. If you don't lose water, but car is still overheating, it could be water pump that's not circulating properly. Your temperature should be increasing rapidly when the water pump is busted though. The above is based on my own experiences, so take with a pinch of salt if necessary.

 

[Rompsku]

thanks for the input pi328!

Have the car for little over a month, it's my second BMW (had a E30 325i).
Everything under the bonnet get super hot, more so at the front of the car. I can barely touch anything connected to the radiator. But my temp never goes over the halfway mark, not even once. And that's what worries me, I'm scared the car is somehow overheating but the temp needle doesn't actually show it. Is that possible?

I don't think I'm leaking coolant, car stands in the garage all day, only really take it out at night, and there is not a drop of oil or coolant anywhere on the floor. Haven't had to top up coolant since I flushed it about 2 weeks ago. Have done about 400kms since then.

What are all the symtoms of a head gasket leak? I get the white smoke and seems to be a airleak on intake side of engine (creates a wooshing sound). But I'm not loosing coolant, power still feels like it's all there and the car generally runs and idles perfectly. Should I be worried?

 

[pi328]

I think you need to compare yours with another one, just to get an idea on what is normal and what is not. Although I live in the northern suburbs and do work in the southern suburbs, Mitchell's Plain is a little bit out of my way. Which other areas do you frequent, so we can maybe meet somewhere in the middle to compare?

It's entirely possible that a temperature sensor (thermostat?) could be out, but you probably would have had bigger issues by now if that was the case. I haven't had head gasket issues yet, so I can't really comment on that.

 

[Rompsku]

My car is pretty much only in MP during the week. I'll be at Canal Walk sometime next week. Might be able to meet up there.

Any body know what the temperature of the coolant should be when the engine is warmed up?

 

[Rompsku]

Really need help here guys, looks like things are getting worse with my E36 328i.

Car is now misfiring at idle, happens on an off. Drove fine for about 60km today, got home and parked it. Started it again a few hours later and it started misfiring. Has been doing it on and off whenever I start the car. Haven't driven it since I discovered the misfire. Standing in the garage while I try to get it sorted.

Also seems to be an air leak somewhere under the intake manifold. Can hear the sound of air blowing/sucking at idle and it sounds like it get's worse when the RPM goes up.

Car also started overheating. It didn't get close to the red line, didn't even get to the 3/4 mark. Moved just past the half mark. This happened when I turned on the heater. Immediately stopped the car and bled the coolant system and it's not overheating anymore, car has been idling for 20 minutes with heater on full blast and needle stays at top dead center, not a hair over it... but still... the coolant get's extremely hot.

Finally, the smoking has gotten worse. Big puff of smoke when I start the car, it dies down almost immediately, but still very faint white smoke while it idles and get's a LITTLE worse when RPM goes up.

So PLEASE fellas, what's wrong with my baby?
What are the steps I should take now? Any checks/tests I can DIY to find the problem before I take it to a mechanic?

 

[Rompsku]

:fencelook:
anybody????

 

[pi328]

PM / e-mail me address and contact details and I'll see what I can do over the weekend, or Monday latest? Not that I'm that mechanically inclined, but I could tell you if the temperature and other noises are normal or not.

 

[Rompsku]

Thanks pi! But really don't expect you take do all that for me. Just thought it might be something that could be easily diagnosed.

Have managed to bribe my wife's uncle to come have a look at the car tonight. He's worked on a few BMWs before, he should be able to give me some definite answers.

Thanks again pi, really appreciate it.
raise:

 

[Rompsku]

so, looks like it's the headgasket...

My uncle in-law came to look at it earlier and all symptoms sounds like headgasket.

We're going to do a full service (Inspection II) on the car next weekend as well as replacing a few bits and bobs under the hood and take it for diagnostics. That should give us a definite answer.

If it is the headgasket, will have it replaced in March.

:argh:

Not the kind of thing you want to hear just after purchasing the car...

 

[racing snake]

1: is the car using coolant?
2: thermostat opens at about 87'c and closes at about 82'c

 

[Rompsku]

1: is the car using coolant?
2: thermostat opens at about 87'c and closes at about 82'c

I don't drive that car much, maybe 300km a week. If it's loosing coolant, it's doing so very very slowly. Haven't noticed a loss in the last 3 weeks.

We did find that a bit of oil is seeping from exhaust side of the engine, haven't had to top up the oil since I did the oil change less than 2 weeks ago, so can't be leaking much, right?

 

[Pfw28]

Having similar issues with 2 E36 316s, eliminated everything bar the radiator on the first, cooling system flush, new water pump, head gasket, removed thermostat, pressure test, the works, only the radiator left. Have noticed that the other one blows cold air from the from the rad when the fan is running,(electric fan), although the pipes are hot, and the needle heading for red. Blocked radiator is the only explanation I can think of, maybe yours too? Feel the air coming out from the fan, (engine side), it should at least be warm, if the rad pipes are hot.

---

Having similar issues with 2 E36 316s, eliminated everything bar the radiator on the first, cooling system flush, new water pump, head gasket, removed thermostat, pressure test, the works, only the radiator left. Have noticed that the other one blows cold air from the from the rad when the fan is running,(electric fan), although the pipes are hot, and the needle heading for red. Blocked radiator is the only explanation I can think of, maybe yours too? Feel the air coming out from the fan, (engine side), it should at least be warm, if the rad pipes are hot.

 

[Rompsku]

Haven't rules out radiator yet, and now that you mention it, the viscous fan seems to be pushing a lot of cold air toward the engine while the rad pipes are very hot (Can't touch them for more than a second), but the radiator feels pretty cool. Will have to get that checked out...

thanks for the input Pfw28!

 

[Pfw28]

Have changed the radiator in no. 2, got warm/hot air from the fan, cooling problem gone. Used a local pirate part (Plexus) supplied by the client. Fit was good, no issues, cost R1020.00. I will report if there are any nasty surprises.

 

[Solo Man]

I had a E39 528i and one day when i had just pulled away from a stop sign the temp gauge went up towards the red. Stopped immediately and felt the pipes, one hot the other stone cold. Replaced thermostat with new from dealer, drove 940km the next day to my home with the needle sitting right in the centre of the gauge. Got home, took the plugs out, put a cardboard over the plugs and turned the starter. About a cup of water hit the cardboard. Long story short, head was cracked, had it stich welded and pressure tested, valves lapped, new gaskets, waterpump, etc., and the car is still running like a charm 50k km later (drove it about a month ago when i was in Upington and it is still silky smooth, no issues what so ever. I think you have a similar problem. First signs were the car would battle to turn over first time in the morning, then slight lumpy idle and then fine and smooth. Thought the battery was the problem but turned out it was water seeping through the cracks in the cylinder head that opened up when cold.
Cost then was about R7,5k all in (BMW mecchie did it after hours for R1000 - will probably get it done for R2k now)

 

[Rompsku]

I think it's only a very small leak in my headgasket, car's performance is still very good and doesn't have any problems with leakage, cold starts, missing coolant or anything like that. Only sign I have so far of problem is white smoke from exhaust and oil seepage on the exhaust side of the engine.

Planning to get it fixed soon though. Just need to get my funds together, have a bunch of other stuff I want to sort out while the head is off.

 

[Kyle]

Generally BMW engine rooms don't have much space in them, especially 6cyl vehicles! so basically there isn't much space for the heat to disperse. Also, the engine compartments are quite well sealed, so there isn't much room for the hot air to escape.

I've had 2 E36's, an E30 and an E46, all 4 cars were noticeably hot under the hood after a good drive. In my opinion its quite normal not to be able to touch the expansion tank after the engines been running for a while.

Why would you want to? :rollsmile:

The fact that your temp gauge is normal is a good sign.

As for the thermostat, turn on your heater to full, if the air is warm then you're ok.