Vanishing Coolant in my 540

[Jehu]

Hi, just bought an E34 540.A month ago i took it to an indy Bimmer shop for a PPI. Among other items they found the coolant res was empty, they filled it. The dealer did a few things on the list and a month later i bought it. The dealer then mentioned they also filled the coolant reseviour. I didn't realise this can be a symptom of a failing Head Gasket. I drove the car about 20 miles home probably the most it had been driven since i took it fpr the inspection.Coolant was now visibly leaking.Seemed to be from below the reseviour. I also read blowing hoses is another symptom of a failing head gasket.As of now there is no smoke from the tailpipe, no apparent coolant in the oil or visa versa, the car starts right up and idles smoothly.This small used car dealer extended their 125,000 miles limit for a 30 day warrenty to me though this car has 129,xxx on the odo. Aside from my anxiety about weather they'll try and pull some fine print BS and back out of this coverage i am waiting to bring it in tomorrow. I am trying to decide weather i'd want to keep it even if they rightheously agreed to fix whatever it needs up to and including the Head Gasket. They share the building with a small mechanic shop where they have their work done.These guys did the tie rod ends, rear controll arm bushing, brakes and muffler clips and i assume they will have them replace whatever hoses blew causing this coolant leak but i really don't feel confident in having them do the Head gasket. The shop is a mess, very dirty, unprofessional in appearnece with hangers on lingering around chatting in some latin tounge with the grease monkey while he works and aside from not seeing any clean space where the parts on my Top End would be kept while doing the HG i just don't know they'd have the expertiese.Anyway i'd like to ask if there are any other common reasons for mysteriously dissapearing coolant than the failing Head Gasket. I think i read the water pump might have a small leak and the coolant is being dissipated by the fan but i didn't see any residue on the fan blades. The Radiator could have a small crack also only leaking when driving and i do think i did hear a bubbling sound inside the radiator while the car was idling, at least i thought it sounded unusual. There was never any evidence of leaking coolant before i got home with my new car.I also have to ask where the mechanic will find the location to attach the pressure guage to test the coooling system pressure and if there is a certain particular guage they will need.Logically thinking i'd surmise the coolant pressure test will show some loss when tested after fixing this newest visible leak .Is that conclusive proof for the failing Head gasket if no visible source for the loss is found ? Will a compression test work or will it need a leakdown test? What is the name of the chemical you can add to the coolant to see if it is interacting with exaust gas? Thanks very much. I want to keep the car but i have a feeling these guys are going to explode when i start talking about replacing the HG... I paid $9,200.00 and it had the Nikasil SB replaced about 40,000 miles ago confirmed by BMWNA.Thanks for the support.Oh one last thing. It came with Rondel style 58 wheels and after the tie rod ends and rear control arm bushing replaced and with the wheels speed balanced there is still the savage shimmy at 50 MPH which the dealer insisted would dissapear with new front tires as these are pretty worn ,does anyone know if these wheels need hubcentric spacers ? Thanks

[joshua43214]

The head gaskets don't normaly blow ont he V8's. If you see coolant leaking down under the resavoir, it is most likely the crossover pipe that runs between the heads. The radiator and the water pump are the weak links in the system, either can make small leaks that wont be noticable without a pressure tester. The heater core is another place that coolant can "disapear" since it will leak through the drain.

Find a shop that actualy has the proper pressure tester adapter, its a rather expensive tool, so most shops don't have them for your car.

[Jehu]

You've really encouraged me a great deal and i am very appreciative for the response.I want to keep the car, i like it so i will have to get them to agree to make sure the car gets tested. Do you think these other weak spots you mention will be easy to find by their shop or are they difficult to get at?I know they have a lift so if these parts are readily accessable i'll have them start with them then they can send it to a BMW dealership of local Independent shop for the pressure test.Again ,thanks alot and i hope you prove to have been right on target.

[Kalevera]

The shop that performed the PPI should have done compression and leak down tests. What are the numbers? They would expose most typical head sealing issues.

What else did the PPI shop have to say about the car? Hopefully they didn't indicate that the car needed rear control arm bushings, as no factory E34 has rear control arms. They should have given you a list of everything that is wrong with the car -- leaking hoses and all. There shouldn't be any question on their part as to what's wrong with the thing. And they shouldn'tve just topped off the reservoir without determining why it was low -- this place sounds suspect. I use a snapon pump/gauge and radiator cap attachment to do a cooling system pressure test. Quick and easy.

Based on the information that we've got on the problem, I'd say that the car has a cracked neck at the reservoir or bad trans heat exhanger lines. The rear manifold that Joshua mentions only seems to leak when the O rings go bad (there are two O rings, one for each metal line between the manifold and the water pump), and I've never seen those go bad unless the car had a hacked water pump install, afterwhich it's pretty apparent that something's wrong. Any of the rubber coolant hoses back there are also suspect, as are cheap hose clamps that frequently are used (and cut the heck out of the hose)

Burning coolant has a distinct odor and look -- I think most people would realize that something's wrong when it happens.

best, whit


Hi, just bought an E34 540.A month ago i took it to an indy Bimmer shop for a PPI. Among other items they found the coolant res was empty, they filled it. The dealer did a few things on the list and a month later i bought it. The dealer then mentioned they also filled the coolant reseviour. I didn't realise this can be a symptom of a failing Head Gasket. I drove the car about 20 miles home probably the most it had been driven since i took it fpr the inspection.Coolant was now visibly leaking.Seemed to be from below the reseviour. I also read blowing hoses is another symptom of a failing head gasket.As of now there is no smoke from the tailpipe, no apparent coolant in the oil or visa versa, the car starts right up and idles smoothly.This small used car dealer extended their 125,000 miles limit for a 30 day warrenty to me though this car has 129,xxx on the odo. Aside from my anxiety about weather they'll try and pull some fine print BS and back out of this coverage i am waiting to bring it in tomorrow. I am trying to decide weather i'd want to keep it even if they rightheously agreed to fix whatever it needs up to and including the Head Gasket. They share the building with a small mechanic shop where they have their work done.These guys did the tie rod ends, rear controll arm bushing, brakes and muffler clips and i assume they will have them replace whatever hoses blew causing this coolant leak but i really don't feel confident in having them do the Head gasket. The shop is a mess, very dirty, unprofessional in appearnece with hangers on lingering around chatting in some latin tounge with the grease monkey while he works and aside from not seeing any clean space where the parts on my Top End would be kept while doing the HG i just don't know they'd have the expertiese.Anyway i'd like to ask if there are any other common reasons for mysteriously dissapearing coolant than the failing Head Gasket. I think i read the water pump might have a small leak and the coolant is being dissipated by the fan but i didn't see any residue on the fan blades. The Radiator could have a small crack also only leaking when driving and i do think i did hear a bubbling sound inside the radiator while the car was idling, at least i thought it sounded unusual. There was never any evidence of leaking coolant before i got home with my new car.I also have to ask where the mechanic will find the location to attach the pressure guage to test the coooling system pressure and if there is a certain particular guage they will need.Logically thinking i'd surmise the coolant pressure test will show some loss when tested after fixing this newest visible leak .Is that conclusive proof for the failing Head gasket if no visible source for the loss is found ? Will a compression test work or will it need a leakdown test? What is the name of the chemical you can add to the coolant to see if it is interacting with exaust gas? Thanks very much. I want to keep the car but i have a feeling these guys are going to explode when i start talking about replacing the HG... I paid $9,200.00 and it had the Nikasil SB replaced about 40,000 miles ago confirmed by BMWNA.Thanks for the support.Oh one last thing. It came with Rondel style 58 wheels and after the tie rod ends and rear control arm bushing replaced and with the wheels speed balanced there is still the savage shimmy at 50 MPH which the dealer insisted would dissapear with new front tires as these are pretty worn ,does anyone know if these wheels need hubcentric spacers ? Thanks

[Jehu]

The shop that performed the PPI should have done compression and leak down tests. What are the numbers? They would expose most typical head sealing issues.

What else did the PPI shop have to say about the car? Hopefully they didn't indicate that the car needed rear control arm bushings, as no factory E34 has rear control arms. They should have given you a list of everything that is wrong with the car -- leaking hoses and all. There shouldn't be any question on their part as to what's wrong with the thing. And they shouldn'tve just topped off the reservoir without determining why it was low -- this place sounds suspect. I use a snapon pump/gauge and radiator cap attachment to do a cooling system pressure test. Quick and easy.

Based on the information that we've got on the problem, I'd say that the car has a cracked neck at the reservoir or bad trans heat exhanger lines. The rear manifold that Joshua mentions only seems to leak when the O rings go bad (there are two O rings, one for each metal line between the manifold and the water pump), and I've never seen those go bad unless the car had a hacked water pump install, afterwhich it's pretty apparent that something's wrong. Any of the rubber coolant hoses back there are also suspect, as are cheap hose clamps that frequently are used (and cut the heck out of the hose)

Burning coolant has a distinct odor and look -- I think most people would realize that something's wrong when it happens.

best, whit

Well the shop was DDD or Three D in Hudson ,NH referred to me as the regional Bimmer Gurus.... They didn't do any compression/leakdown test. They charged me $90.00. The part which i called a rear control arm bushing was in fact the left rear sway bar link which the dealer claims to have had fixed. Now that i look at the list again i see upper caster arms and bushings which the dealer didn't claim to have done.It says the on board computer is inoperable but though the lighted display is out, i noticed when i pressed the 'CODE' button , one of the dash read out displays went off which proved repeatedly to be the case so it seems it may just be a bulb. I checked the fuses and they're all good( d ropped one i was checking down into the box, any way to get in underthere?). I didn't see any information in the owner's manual about changing the bulb for the On board Computer, do you happen to know the way?I agree it was lame of the PPI shop not to go into more detail about the coolant but perhaps and hopefully it is becasue their experinece told them with the 540 it is usually not a head gasket symptom and the cause is to be found elsewhere among the items you've listed. Thanks. I'll be around.... Oh yah the other problem i'm having is reprogramming the Radio code , i have the code and was told to just input it with the radio keypad numbers . It isn't doing the trick. Is there another button i need to press in concert or before or after or do i need to hold the buttons down for a certain number of seconds? I also just found it has the 6 CD changer in the truck which i did not know...

[Jehu]

I found it! Under the hood, right in the driver side corner against the fierwall is a block assembly with four hoses going in and out, i think its the Heater Valve.There is a stream of coolant leaking from this where the S hose from the water pump enters /or exists the unit. I was told it cost $145.00 and is easy to do yourself but the coolant system needs to be bled . Any tips on doing this appreciated.

[joshua43214]

Clamp off all 4 hoses. remove the hoses. remove the water valve. reverse to install. no bleeding needed. just add about 1 cup of coolant to cover loss, if any.

If you have no clamps, put a pan under the car, remove the hoses and keep them elevated as best you can so you don't siphon out the heater core. still no bleeding needed, just run the engine with the heat on high until its hot ad top up the resavoir.

[RTV]

Picture of aux. waterpump and heater valves
2967

Mine had a leak in the pump. While waiting for new pump, I just bypassed the pump. Move the hose from engine --> pump to where the "S" hose is connected to the heater valve. Works just fine.

I found that the easiest way to get the assembly out was to disconect all the hoses (Just remember how it hangs together), losen both cables and remove the three nuts holding the unit. Tight as h... came out finally.

[Jehu]

Picture of aux. waterpump and heater valves
2967

Mine had a leak in the pump. While waiting for new pump, I just bypassed the pump. Move the hose from engine --> pump to where the "S" hose is connected to the heater valve. Works just fine.

I found that the easiest way to get the assembly out was to disconect all the hoses (Just remember how it hangs together), losen both cables and remove the three nuts holding the unit. Tight as h... came out finally.
I was just going to Update this thread to say after i got a telescoping Mirror i found it is indeed the Aux Water Pump. Leaking from between the two sections.So your post is just what the doctor ordered.Tell me though, in spite of what i think i see and understand, that being this assembly is above the level of the reseviour which is of course empty anyway, can i do this in my Condo parking space without dumping liters of coolant everywhere or will i get some backflow from somwhere like the water pump?Also i don't suppose i could just use some waterproof epoxy and some kind of supertape or open that cylindar and replace the seal in there? Does that Aux Water Pump just stand by as back up incase the main one croaks? Thanks a million.

[632 Regal]

mine was pissing last year, new ones are like 100 bux from BMAparts.com

No bleeding required on the V8 :D

[RTV]

I was just going to Update this thread to say after i got a telescoping Mirror i found it is indeed the Aux Water Pump. Leaking from between the two sections.So your post is just what the doctor ordered.Tell me though, in spite of what i think i see and understand, that being this assembly is above the level of the reseviour which is of course empty anyway, can i do this in my Condo parking space without dumping liters of coolant everywhere or will i get some backflow from somwhere like the water pump?Also i don't suppose i could just use some waterproof epoxy and some kind of supertape or open that cylindar and replace the seal in there? Does that Aux Water Pump just stand by as back up incase the main one croaks? Thanks a million.

Took mine out with almost full reseviour. Just held the hoses as high as possible, almost no spill.

I opened the pump and there was no gasket, but there was a plastic "cap" that separates the motor and the coolant that had cracked. not possible to fix it. Open it and you'll see. Got new pump approx 150Euro.

I by-passed the pump while waiting for new pump, everything worked just like before. Drowe like this for over two weeks... Seems like the pump is fitted just to get heat in car faster.

The pump runs together with the main pump when heat on in car. Stops when heating is turned off. Seem to operate together with the heater valve.