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Discussion Starter #1
Hi, some engine oil is finding its way into the coolant.

It is not a massive amount, and it is only a one way problem - there is no sign of water contaminating the engine oil.

The car runs and starts fine - no overheating.

I suspected the heat exchange oil cooler - but there isn't one on my model apparently - 3.0 V6 1999.

I heard somewhere that re-torquing the heads is the first port of call....?

Has anyone else had this problem and fixed it without doing a massive top end head gasket job?
On the other hand the engine is on 132000 - so maybe a top end rebuild is due???
 

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When the coolant is cool dip the header tank with a J cloth. If the oil is only a very thin layer on the surface and below is clear antifreeze, don't worry. Ignore it.
 

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You can try what i did. Fill the expansion bottle to top and i mean top. Then start engine. Rev it a bit and watch coolant do you see bubbles coming out? Well in my case they did so im in progress of changing the head gasket. Problem is it brings so many other things with it.
Head gasket
Resurface head it self
All new gaskets (set for head gasket change)
Maybe do belt,water pump change as well since it has to come off anyway

BUT i hope its nothing really in your case ;)
 

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No idea if its relevant, but V6 164s used to do this unless you re-torqued the cylinder heads. I imagine the newer V6 engines use those "stretch" bolts? IF not, maybe re-torquing the head bolts (COLD) will help? Mine did it. I should have been suspicious of the brand new expansion tank and the crystal clear antifreeze in it when I first bough the car...

...After 50 miles there was brown scum in it! I got the last laugh though - re-torquing the head bolts cured it!
 

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Discussion Starter #5
Thank you everyone for your replies. I will re-torque the heads and keep an eye on it -and feedback. Oh the joys of these beautiful old masterpieces eh?
 

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All the Busso V6 engines use studs in the block so no stretch bolt worries. A re-torque is always a smart thing to try first. Just costs an hour or two of effort. Don't forget to oil the nuts & washers BTW and you'll need an angle gauge as well as a torque wrench. Later engines use torque + angle (24-26Nm + 240 degrees). On the 12V, I used to go + 10% on a re-torque.

As already noted, a full headgasket job is going to end up costing a few quid just in the parts. If you do end up having to go this way, only use either OEM gaskets or Reinz or Spesso (OEMs will be one of those two brands). Avoid cheap pattern parts.

Good luck!
 

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Oil in coolant

Similar woes from my TS. Been tested and has carbon monoxide in coolant :(

Driven well over 1000 miles like that and no issues at all. Tempting fate though

Would the re-torque work for 4 cylinder leaky head gasket?
 

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Can't hurt to try it at least. I'm not familiar with the modern TS engine - last Alfa 4 pot I worked on was from 1964, but there's a chance the head bolts will be accessible without having to strip too much off.
 

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Discussion Starter #10
ok -so there is a nice happy flow of bubbles coming up to the expansion tank... but there is no carbon monoxide - the test fluid stays nice and blue. Mobitech describe it as a "puzzler"....

as I said - no coolant is leaking, and the engine oil is like new in the sump....but with the bubbles coming up is also the oil....so, the question is....how could the head gasket leak oil but not combustion gasses? Is that possible???
 

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I guess so depending on where the head gasket fails. There are three things to keep separate, combustion chamber, oil pathway and water/antifreeze pathway. I would say the combustion chamber is intact, but the material between the oil and water passages may have failed.

HTH
 

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I agree. All it proves is that the damage to the gasket isn't between one of the combustion chambers and the water jacket. I know that the old 164s sometimes did this and you could cure it by re-torquing the head bolts but I've a feeling that the newer engines use those "stretch" bolts so there would be nothing to be gained by it and there's the chance of snapping a bolt.
 

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Discussion Starter #13
When the coolant is cool dip the header tank with a J cloth. If the oil is only a very thin layer on the surface and below is clear antifreeze, don't worry. Ignore it.
OK - so this is the verdict of Mobitech...
When the engine gets up to full temperature then the air bubbles stop coming through...
It seems that when the thermostat is shut, then the movement of air around the breather system is picking up a slight bit of oil from the top of the engine somewhere. as soon as the thermostat opens then the "phenomenon" ceases!!
So thanks aggy8888 - seems you could be right - don't worry oh me of little faith!

So sighs of relief all round - it is just a quirk in the system of this particular Busso...
I am taking the 166 to Weisbaden in September to parade it to the Germans - so that will prove forever whether it is just a few drops when the engine is cold - or not - as the case may be!
 

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there is that Steel Seal head gasket wonder treatment for £50 or so that fixes 99% of head gasket failures, seen as your issue is relatively small it may be worth a punt to fix it.

HTH
 

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It seems that when the thermostat is shut, then the movement of air around the breather system is picking up a slight bit of oil from the top of the engine somewhere. as soon as the thermostat opens then the "phenomenon" ceases!!
Rather than being specifically related to the thermostat, it sounds to me more like the expansion of the block and heads as they heat up (which will obviously coincide with the thermostat opening) is squashing the gasket enough to seal it properly. So when the engine is cold, you aren't getting full compression of the gasket at a weak/failed spot, but it's fixing itself once the engine heats up and expands.

So, have you tried re-torquing the heads?

So long as it's only a small amount of oil in the coolant, and none going the other way, I'd be tempted to leave it (bar re-torquing the head of course) for as long as you can live with it. Leak sealers like K-Seal will probably fix this in a shot as it sounds like it's an early and small leak, but I'd use that as a last resort. I'm not speaking from first hand experience, but lots of people say these products block coolant paths (like arteries getting clogged with cholesterol) and once they are in the system they are a pain to clean out further down the line. I'm not completely against the idea, and have used both K-Seal and Radweld on one of my cars with a very severe leak caused by cylinder block face that is not 'true', but it's worth being cautious and considering all the options and implications before you jump in to something like that.
 

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Discussion Starter #16
This problem has not got any worse....in any case the leak stops as soon as the engine is warm.
K-seal etc is for coolant leaks....I am keeping an eye as it does seem that the coolant level drops over time...but these treatments don't fix oil leaks.
 

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Hi everybody,
I think I am facing the same issue on my 99 GTV 3.0 V6. The engine runs absolutely fine :no smoke at the back, decent power (did not take the cylinders compression readings, but the GTV accelerates almost as fast as my Merc CLK500, so...), no oil consumption though it has done 120 KMiles.

The oil in engine thing has started ~30 Kmiles ago and is getting gradually worst. See attached pictures.

Since I am currently doing my cambelt, I was thinking of removing the ehads and change both HG. However , reading the threads above, I am now thinking of re-tightining the heads only (+ clean the cooling system too).

Could you please confirm it is a good idea or whether I should go for the HG. The cost is not the same as well as the necessary time to do so.
What is your opinion? What are the tightening torque values on the V6 3.0 24V and the tightening sequence please?
 

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Discussion Starter #18
Hi everybody,
I think I am facing the same issue on my 99 GTV 3.0 V6. The engine runs absolutely fine :no smoke at the back, decent power (did not take the cylinders compression readings, but the GTV accelerates almost as fast as my Merc CLK500, so...), no oil consumption though it has done 120 KMiles.

The oil in engine thing has started ~30 Kmiles ago and is getting gradually worst. See attached pictures.

Since I am currently doing my cambelt, I was thinking of removing the ehads and change both HG. However , reading the threads above, I am now thinking of re-tightining the heads only (+ clean the cooling system too).

Could you please confirm it is a good idea or whether I should go for the HG. The cost is not the same as well as the necessary time to do so.
What is your opinion? What are the tightening torque values on the V6 3.0 24V and the tightening sequence please?
I have since seen spots of oil in a few 3.0 busso coolant tanks...
As for the oil in my coolant tank...it doesn't seem as bad as it was 19,000 miles ago in 2013...I don't even think about it any more.

My local Alfa indie did a test on the gas that was bubbling up and it was fine...he thought it something to do with the breather system...see above.
TBH a little oil in the coolant could help the life of the thermostat and the water pump, mine sits dead on 90 degrees and uses no oil at all (after 7,000 miles) since I changed to fully synthetic last year.

If I were you I would get that bubbly test done and if there are no combustion gases then just leave it.
 

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I have since seen spots of oil in a few 3.0 busso coolant tanks...
As for the oil in my coolant tank...it doesn't seem as bad as it was 19,000 miles ago in 2013...I don't even think about it any more.

My local Alfa indie did a test on the gas that was bubbling up and it was fine...he thought it something to do with the breather system...see above.
TBH a little oil in the coolant could help the life of the thermostat and the water pump, mine sits dead on 90 degrees and uses no oil at all (after 7,000 miles) since I changed to fully synthetic last year.

If I were you I would get that bubbly test done and if there are no combustion gases then just leave it.
Helle

If you Google the topic you will find a thread somewhere in this forum discussing contaminated coolant. Seems like all Busso engines tend to leave a gray layer in the expansion tank which can be mistaken as oil. I was afraid my engine had a head gasket problem, but oil is ok and does not use A drop of water. I cleaned the expansion tank and the layer is now back.

Br Martin
 
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