ugh! motor oil leaking on waterpump 91-300D - PeachParts Mercedes-Benz Forum

vstech · #1 08-09-2010, 10:20 PM

only path I can see is the head gasket...
anyone got a fix for this leak or another possible source on the 602 turbo?
the vc is dry and clean, the manifold has no oil on it. there is oily residue on the turbo feed and drain, but nothing between them.
somebody point out the gremlin that leaks oil on the waterpump ppplease...
my customer does not have the money for a head gasket replacement...
the car runs SOOO strong otherwise.
however, it does run a tad hot, and the hose does not get hard after a drive up to temp...
I'm changing the fan clutch in the morning, and pressure checking the coolant system... it's got green coolant in it!

Jetmugg · #2 08-09-2010, 10:23 PM

Vacuum pump? My original vacuum pump sprung a leak from the front cover - it was tough to figure out where the oil was coming from.

SteveM.

babymog · #3 08-09-2010, 10:31 PM

Mine did too, the crimped-on cover rattled also.

vstech · #4 08-09-2010, 10:36 PM

I'll give serious inspection to the vacuum pump, but it looks to be coming from above the water pump. it's good news that the oil could be traveling from another source, thanks! the vp could be spraying oil up on the head, and it's trickling down onto the wp...
of course, a new vp is not much cheaper than a head gasket replacement...

layback40 · #5 08-09-2010, 10:43 PM

!/2 a turn on each of the head bolts may help. Dont break any though.

babymog · #6 08-09-2010, 10:44 PM

Quote:

Originally Posted by layback40

!/2 a turn on each of the head bolts may help. Dont break any though.

Seriously? They're stretch-bolts, doesn't seem like you could do anything scientific other than verify that they are at least at the initial tightening torque.

layback40 · #7 08-09-2010, 10:59 PM

Jeff,
The car has run hot a few times.
Stretch bolts do elongate over time.
!/2 a turn may bring them back into their stretch region again.
It is just a simple thing that has worked for many before.

babymog · #8 08-10-2010, 09:51 AM

I understand that it might work, the only thing I'm saying is that you can't get the correct/even clamping force that way.

Perhaps turning them all to the original torque, if you find some that move, then you have verified that the bolts have loosened/elongated and can resume the head final-torque sequence.

I think that the more likely scenario is that the bolt hole in the head has yielded, but that's another discussion.

It is hard to argue with a method that works, if it has been working though, and there's a 602 head for sale in the classified section currently.

vstech · #9 08-10-2010, 10:25 AM

if any are loose, should I pull them, and replace the loose ones as an attempt to fix? I"m still hoping for vacuum pump...

layback40 · #10 08-10-2010, 07:56 PM

I have seen a motor (not MB) with bubbles in the coolant (bad head gasket) & the head was torqued down 20 ftlb more than the spec & the bubbles went away. The truck has done 50k miles since with no problems.
My brothers C280 had a slight oil leak out of the head gasket, we tensioned it up 10 ftlb more than the spec & the oil leak is gone, that was 10k miles ago, we still have our fingers crossed on that one !!!
The 60x motors have an interesting requirement for head tensioning, that is why I suggested 1/2 a turn. If it is going to take Mega torque to do that, I am sure vstech is smart enough to realize not to go that far.

Good Luck !!!

Billybob · #11 08-10-2010, 10:42 PM

Quote:

Originally Posted by vstech

only path I can see is the head gasket...
anyone got a fix for this leak or another possible source on the 602 turbo?
the vc is dry and clean, the manifold has no oil on it. there is oily residue on the turbo feed and drain, but nothing between them.
somebody point out the gremlin that leaks oil on the waterpump ppplease...
my customer does not have the money for a head gasket replacement...
the car runs SOOO strong otherwise.
however, it does run a tad hot, and the hose does not get hard after a drive up to temp...
I'm changing the fan clutch in the morning, and pressure checking the coolant system... it's got green coolant in it!

With regard to the oil on the water pump aspect, there are only a couple possibilities. Of course cleaning the area so you can determine the direction from where any oil is being deposited from. A stripe of oil on the hood pad should point to a leak from the front of the engine somewhere.

The vacuum pump spewing oil some how, ought to be fairly easy to identify. The PS pump can loose its seal and sling oil around the front of the engine also, lucking that will be easier to determine as the problem as the PS fluid isn’t as black as crankcase oil! I would consider the crankshaft main seal the next culprit if you determine the oil is coming from somewhere in front of the timing cover. Any oil getting past that seal ends up being slung around by the balancer then the belt and pulleys eventually.

As far as the cylinder head, I would first take a look at the tensioner and the aluminum seal ring under it, that is ported directly into pressurized oil and often sort of weeps crankcase oil, and it’s sort of above the water pump. Could be a $2 & 5 minute fix if that’s the oil source. If you look at the engine the portion of the cylinder head above the water pump it is the timing chain chase which is the front 3” of the cylinder head. That area of the head gasket is more prone to leak oil outward than area’s surrounding the cylinders and valves. There are the two 8 mm Allen head bolts inside the chase and the two 13 mm hex bolts which also serve to secure the fuel filter head/stand in place which clamp that area of the gasket. If you find that area is the source of the dripping oil you could try tightening the Allen head bolts there. If that doesn’t do the trick in a similar situation on a M110 oil leak the owner opted (he had just had the head gasket replaced so he wasn’t going to have it redone to fix the problem) to try sealing the leak from the outside using the MB black sealant which comes in the large syringe. After cleaning the area with carb cleaner and compressed air 5 or 6 times put a bead of sealant over the block/gasket/cylinder head interface and let it cure a day or two, this was done a couple years and probably 20 K ago and it’s still dry.

I would hesitate screwing with the actual cylinder head bolts in any way before I had exhausted all the other potential problem areas. It’s fairly easy to have a problem if you don’t follow the FSM procedure with care; doing some tightening then maybe having too loosen and retighten the bolts for me would be a last resort to be avoided. Honestly I’d probably never do it, if I found loosened bolts I’d have to check the how and why and would end up replacing a gasket if it was leaking. Of course if you’re working for a paying customer they call that shot, but I would take no responsibility for any outcome.

vstech · #12 08-10-2010, 11:34 PM

Quote:

Originally Posted by Billybob

With regard to the oil on the water pump aspect, there are only a couple possibilities. Of course cleaning the area so you can determine the direction from where any oil is being deposited from. A stripe of oil on the hood pad should point to a leak from the front of the engine somewhere.

The vacuum pump spewing oil some how, ought to be fairly easy to identify. The PS pump can loose its seal and sling oil around the front of the engine also, lucking that will be easier to determine as the problem as the PS fluid isn’t as black as crankcase oil! I would consider the crankshaft main seal the next culprit if you determine the oil is coming from somewhere in front of the timing cover. Any oil getting past that seal ends up being slung around by the balancer then the belt and pulleys eventually.

As far as the cylinder head, I would first take a look at the tensioner and the aluminum seal ring under it, that is ported directly into pressurized oil and often sort of weeps crankcase oil, and it’s sort of above the water pump. Could be a $2 & 5 minute fix if that’s the oil source. If you look at the engine the portion of the cylinder head above the water pump it is the timing chain chase which is the front 3” of the cylinder head. That area of the head gasket is more prone to leak oil outward than area’s surrounding the cylinders and valves. There are the two 8 mm Allen head bolts inside the chase and the two 13 mm hex bolts which also serve to secure the fuel filter head/stand in place which clamp that area of the gasket. If you find that area is the source of the dripping oil you could try tightening the Allen head bolts there. If that doesn’t do the trick in a similar situation on a M110 oil leak the owner opted (he had just had the head gasket replaced so he wasn’t going to have it redone to fix the problem) to try sealing the leak from the outside using the MB black sealant which comes in the large syringe. After cleaning the area with carb cleaner and compressed air 5 or 6 times put a bead of sealant over the block/gasket/cylinder head interface and let it cure a day or two, this was done a couple years and probably 20 K ago and it’s still dry.

I would hesitate screwing with the actual cylinder head bolts in any way before I had exhausted all the other potential problem areas. It’s fairly easy to have a problem if you don’t follow the FSM procedure with care; doing some tightening then maybe having too loosen and retighten the bolts for me would be a last resort to be avoided. Honestly I’d probably never do it, if I found loosened bolts I’d have to check the how and why and would end up replacing a gasket if it was leaking. Of course if you’re working for a paying customer they call that shot, but I would take no responsibility for any outcome.

VERY nice response! thank you very much!
the motor is very clean except for the small trail from the corner of the head dripping on the waterpump. I will totally go over it with a fine tooth comb, and if no other sources are found, I will inspect the timing cover. and go further and see what I see.