New x5 3.0 owner - Head Gasket Concerns

[blatant]

Hi all,
I have been a lurker for a while on xoutpost but fairly active on bimmerforums and m3forum. I currently own an e46 m3, e36 m3 and recently acquired an e53 x5 3.0 2001.

The plan is to get rid of my e36 m3 and make the X my daily. I purchased the car this past Sunday with the impression the car needs its head gasket changed. I acquired it fairly cheap which makes either a head gasket swap or engine swap worthwhile.

Last night I tore into it. I drained coolant and oil. The oil was really black but I could not see water or coolant in it. The coolant on the other hand looked to have a good amount of oil in it. It was a mix of blue, green and oil. My impression is that the previous owner knew he had an issue, as I can tell there are all new hoses, radiator and thermostat....so that would lead me to think that he drove it around with the head gasket issue for a while.

I have completed 3 headgasket jobs on s50 + s52 engines but I have some concerns with the all aluminum m54.

1. Since the x5 most likely has been driven for a while with the head gasket issue, am I more than likely going to have an issue with the head bolts stripping in the aluminum block?
2. I have never timeserted before, so that concerns me. How difficult is it?
3. The coolant system has oil in it now, including the heater core. Has anyone ever used a cleaner to get rid of the oil? What is a procedure I should follow to clean out the system?
4. I have not run a compression test (have it) or leak down (do not have), would anyone recommend doing this before I tear into doing the head gasket job? The amount of oil in the cooling system made me just jump to "change the head gasket" mode. Like...can power steering leak into radiator.

I'd appreciate any help with this.

[Scott ZHP]

Originally Posted by blatant

Hi all,

I have completed 3 headgasket jobs on s50 + s52 engines but I have some concerns with the all aluminum m54.

1. Since the x5 most likely has been driven for a while with the head gasket issue, am I more than likely going to have an issue with the head bolts stripping in the aluminum block?
2. I have never timeserted before, so that concerns me. How difficult is it?
3. The coolant system has oil in it now, including the heater core. Has anyone ever used a cleaner to get rid of the oil? What is a procedure I should follow to clean out the system?
4. I have not run a compression test (have it) or leak down (do not have), would anyone recommend doing this before I tear into doing the head gasket job? The amount of oil in the cooling system made me just jump to "change the head gasket" mode. Like...can power steering leak into radiator.

I'd appreciate any help with this.

Welcome!

I'd suggest some more diagnostic work before concluding you have a head gasket failure. The trans-cooler can fail and allow engine coolant to mix with trans oil. I'd be checking that first. Smell your exhaust, is it "sweet" smelling? Maybe borrow or rent a leak-down tool if you have a compressor.

Head bolts wont strip coming out, but they will strip when you attempt to torque new ones into the (annealed from overheating) block.

Timeserts are not particularly difficult to install, just be patient and don't rush it. Ensure the drill is SQUARE to the block.

As mentioned, I like to be really heavy on the diagnosis before buying any parts to be certain what I'm dealing with.

Just saw a low mileage M54 complete longblock from an X5 from en eBay seller I trust. I think the buy-it-now was $1200, the X had 96k miles on it.

(edit: 102k miles, $1250... I was close, lol)

BMW Engine Motor M54 Z4 Z3 3 0i E46 330i 330CI XI E39 E60 530i E53 x5 3 0i | eBay

[blatant]

Originally Posted by Scott ZHP

Welcome!

I'd suggest some more diagnostic work before concluding you have a head gasket failure. The trans-cooler can fail and allow engine coolant to mix with trans oil. I'd be checking that first. Smell your exhaust, is it "sweet" smelling? Maybe borrow or rent a leak-down tool if you have a compressor.

Head bolts wont strip coming out, but they will strip when you attempt to torque new ones into the (annealed from overheating) block.

Timeserts are not particularly difficult to install, just be patient and don't rush it. Ensure the drill is SQUARE to the block.

As mentioned, I like to be really heavy on the diagnosis before buying any parts to be certain what I'm dealing with.

Just saw a low mileage M54 complete longblock from an X5 from en eBay seller I trust. I think the buy-it-now was $1200, the X had 96k miles on it.

(edit: 102k miles, $1250... I was close, lol)

BMW Engine Motor M54 Z4 Z3 3 0i E46 330i 330CI XI E39 E60 530i E53 x5 3 0i | eBay

Thanks for the thorough response, I appreciate it!

I will have to fill the X back up with oil and coolant to check it all out again. I will do that and report back.


As far as the trans fluid in the coolant, I'd assume that would go both ways. So I should be checking the trans fluid as well for coolant?
How can I tell if the oil in my coolant is burned/brown ATF or engine oil?

[g300d]

Came here to post as above...it could be the trans oil. Experienced it first hand.

I noticed mayo on the rad cap on one of my weekly checks. Car ran fine. Oil in coolant, no coolant in oil.

Thought head gasket as well but I wanted to rule out everything else before tearing into the engine so I checked the trans cooler first. Removed it from the car and had it pressure tested at a radiator shop. It failed pressure testing.

Replaced this first and did ATF and coolant replacement. No more mayo luckily.

[Scott ZHP]

Originally Posted by blatant

Thanks for the thorough response, I appreciate it!

I will have to fill the X back up with oil and coolant to check it all out again. I will do that and report back.


As far as the trans fluid in the coolant, I'd assume that would go both ways. So I should be checking the trans fluid as well for coolant?
How can I tell if the oil in my coolant is burned/brown ATF or engine oil?

Did the seller level with you about the issue? If you didn't or can't get a straight answer from the seller, I'd probably drain the oil, and the coolant. Flush the expansion tank and the rad of as much co-mingled crap as you can get out - open the tap on the bottom of the rad - little blue screw. Maybe yank the water pump and clean there too. Then start with a baseline of fresh fluids. You could drain the trans oil and have a look at that too; if it looks like chocolate milk, you've found your problem. Lots of opinions about which trans fluid to use/not to use. Be certain you know what you're going to refill with prior to draining. I'd replace the filter too, just because you never know when it was last changed. If you just want to test it, you can open the fill plug and suck some fluid out with a syringe/short hose.

If it's still not obvious, for a few bucks, add a UV dye like this to the engine oil:

NAPA AUTO PARTS

Run it for a while, watching the temp gauge like a hawk, and then test the coolant for presence of oil+dye. If you have dye in the coolant, you're getting oil in the water jacket. No dye present in the coolant, the oil is from somewhere else, likely the trans. The dye is harmless, you need a UV flashlight to see it; another $10-15 at Amazon.

I wish I had a dollar for every thread where someone chimed in with a diagnosis of a bad head gasket. Unless it's overheated, they don't fail. Not saying that isn't your problem, but I like to be sure before I tear into things.

Good luck.

[blatant]

Appreciate the response everyone. I have pulled the transmission cooler and drained the trans oil. The oil was black but did not look like water was in it. I am dropping the cooler off after work to have it pressure tested before I continue. Does anyone know what the trans pressure through the cooler should be? The trans shop wanted to run 100 psi through it, but that seemed to high for me. I was thinking 20 psi tops.

The seller had no clue or pretended to have no clue. So I am on my own as far as that. If the trans does pass the pressure test, then I will clean everything out and watch everything on short trips. I like the UV dye idea, I will look into that.

[Helihover]

100 psi seems a lil high.

Going back to my younger days dabling with pressure tests, the tests seemed more focus on how long the system held air, not so much the pressure. I believe we would run around 80 psi on copper and 15 psi on pvc.

[Scott ZHP]

The exchanger has two loops in it.

Coolant loop needs to handle about 28psi or about 2bar (the rad cap pressure).
Trans oil loop, dunno what it runs at, but I wouldn't do more than the max coolant pressure of 28psi.

If it's leaking in either loop, they'll know it immediately.

[blatant]

Ok, appreciate you confirming that. He is going to test it tomorrow, I will post back the results of the test.

Honestly, I would much prefer to change out the trans cooler vice the head gasket. Fingers crossed but I definitely do not have my hopes high.
Appreciate the moral support everyone has been providing.

[bcredliner]

I would have done more troubleshooting to pinpoint the problem. I would have checked the trans fluid level before the drain or measured what was drained which would have given more indication the trans cooler is the problem before removing it. I would also have checked for cylinder related trouble codes as well. Hopefully, the trans cooler is the problem.