[Z10M5]

I drive a 2014 535i RWD at 153,000 miles. For a while now i’ve been having disappearing coolant with not leaks, i took it to a reputable shop in socal and they did a block test and told me that i either have a cracked/warped head or head gasket leak. My car has never been over heated and other than the disappearing coolant there are no other symptoms, the car is very well maintained and if the mileage was covered you’d never know it has that many miles. They said a job like that would be ~$6k-$8k depending on what’s actually faulty. I did some research and i think all the parts that are needed to to the job are ~$1.5k and this includes the “while you’re in there” replacements. My question is, can this job be done while the engine is still in the car, i know it might be tight but seems doable with a little of blood, sweat and tears. If you have any experience please share it. Thanks.

[ezaircon4jc]

I would check the coolant reservoir first. That seems to be a common failure point with higher mileage/years. Look for whitish residue around the tank.

A blown head gasket will also cause whitish smoke (not to be confused with normal condensation) out the tail pipes.

[Z10M5]

Originally Posted by ezaircon4jc

I would check the coolant reservoir first. That seems to be a common failure point with higher mileage/years. Look for whitish residue around the tank.

A blown head gasket will also cause whitish smoke (not to be confused with normal condensation) out the tail pipes.

I replaced the coolant reservoir and some lines about a year ago and everything checks out, im telling you everything is normal except for the disappearing coolant and the block test the shop did.

[95blkmax]

What exactly did the shop test? I just ask because it seems like a vague description of what could be happening.

Do you have any milky residue in the engine oil? Any signs of coolant in your air pipes passed the turbo?

This would have been MY procedure:
- Visual search for any obvious leaks in the coolant circuit
- Pressurize cooling system and look for any active leak (confirmed by a pressure drop after a few minutes)
- If no coolant seen leaking anywhere at this point, move on to the engine and perform compression test
- If all cylinders are within 10% from each other, perform cylinder leakdown test

At your mileage these would be the common spots- expansion tank (you already replaced), expansion tank cap, casing of the water pump itself, the plastic mickey mouse fitting (coolant hose end at the front of the cylinder head that goes to the t-stat), radiator at the plastic end tanks, oil filter housing

Then the not so common (but not surprising) items due to age that I've seen- transmission heat exchanger failure (more common with the E90 LCIs), heater core, turbo coolant lines

[Z10M5]

Originally Posted by 95blkmax

What exactly did the shop test? I just ask because it seems like a vague description of what could be happening.

Do you have any milky residue in the engine oil? Any signs of coolant in your air pipes passed the turbo?

This would have been MY procedure:
- Visual search for any obvious leaks in the coolant circuit
- Pressurize cooling system and look for any active leak (confirmed by a pressure drop after a few minutes)
- If no coolant seen leaking anywhere at this point, move on to the engine and perform compression test
- If all cylinders are within 10% from each other, perform cylinder leakdown test

At your mileage these would be the common spots- expansion tank (you already replaced), expansion tank cap, casing of the water pump itself, the plastic mickey mouse fitting (coolant hose end at the front of the cylinder head that goes to the t-stat), radiator at the plastic end tanks, oil filter housing

Then the not so common (but not surprising) items due to age that I've seen- transmission heat exchanger failure (more common with the E90 LCIs), heater core, turbo coolant lines

Thank you for your input, so here’s the full story. About a month ago i took my car to this shop for an oil pan gasket job because mine was leaking and i didn’t have the time or patience to do it myself. They then told me that my thermostat was leaking and they recommended that i replace the water pump and since the car was apart already they would only charge me $100 for labor, so i agreed to do that job. After a couple of days when i got the car back, the next day in the morning there was coolant puddle under my car (front passenger side) i told them about it and they said to bring it in, i took it in and after a couple of days they said they pressure tested the system and found no leaks and said “it was most likely a bubble in the system” which is weird but ok. Next day after i got the car back, i find another puddle under the car in the exact location, so i tell them about it and they say to bring it in, after taking it to them, they told me that the coolant system is too pressurized and they will do a block test (the blue fluid that turns yellowish when it detects exhaust gases in the cooling system) so a couple of days later they say that my radiator is leaking and the block test failed which means exhaust gases are somehow getting in my cooling system. They said its either a blown head gasket or a cracked/warped head. As of now im not sure but apparently i have a leaking radiator which idk if i believe but i know that the car is leaking from somewhere and i have a new radiator sitting next to me in a box waiting to be installed. There is no milky residue anywhere and no white smoke from the exhaust pipes. The weird thing is the car doesnt actively leak, its only when its left overnight, i really need to get dirty and get to the bottom of this.

[ezaircon4jc]

Is the cap new?

[Z10M5]

Originally Posted by ezaircon4jc

Is the cap new?

Yes both the cap and reservoir are new and original BMW parts.

[95blkmax]

At this point I'd highly suggest you take it to have BMW do a diag on it for coolant leak. You pay for that diag, and depending on what they find it would be your choice if you want to have this shop perform the repair the dealer found, or just have the dealer take care of it.

Im only suggesting this because Im still feeling like proper diag'ing was not done. They did the block test and it failed so there's exhaust in the coolant. Great... what cylinder(s) is causing it? Cylinder heads dont just warp. The engine has to have had a severe overheating for that to have happened. Even if so, if exh gases are making their way into the coolant, during overnight cooling the coolant will often find its way back (as the coolant system is under pressure but the cylinders would loose pressure faster) so you'd likely see signs of dry coolant on the spark plugs. Additionally, I can see how a warped head could leak coolant to the outside and perhaps all gather in one spot to pool under the car. But you'd also see the signs of coolant run-off- which tells me that the shop didn't even do a visual inspection.

I just feel there's a whole lot of half-a$$ing by the shop and they're giving you the run-around. I highly encourage you to take it in to have a proper diag done by either BMW or a competent reputable indy BMW-specialist... and based on what they find you can make an educated decision as to how to proceed

[Z10M5]

Originally Posted by 95blkmax

At this point I'd highly suggest you take it to have BMW do a diag on it for coolant leak. You pay for that diag, and depending on what they find it would be your choice if you want to have this shop perform the repair the dealer found, or just have the dealer take care of it.

Im only suggesting this because Im still feeling like proper diag'ing was not done. They did the block test and it failed so there's exhaust in the coolant. Great... what cylinder(s) is causing it? Cylinder heads dont just warp. The engine has to have had a severe overheating for that to have happened. Even if so, if exh gases are making their way into the coolant, during overnight cooling the coolant will often find its way back (as the coolant system is under pressure but the cylinders would loose pressure faster) so you'd likely see signs of dry coolant on the spark plugs. Additionally, I can see how a warped head could leak coolant to the outside and perhaps all gather in one spot to pool under the car. But you'd also see the signs of coolant run-off- which tells me that the shop didn't even do a visual inspection.

I just feel there's a whole lot of half-a$$ing by the shop and they're giving you the run-around. I highly encourage you to take it in to have a proper diag done by either BMW or a competent reputable indy BMW-specialist... and based on what they find you can make an educated decision as to how to proceed

Thank you for your input.