Oil in the radiator. NH 3 litre.

[alchemysa]

It looks like my cooling and lubrication systems are swapping fluids. In particular I've accumulated a fair amount of engine oil in my radiator coolant. I think theres also a little bit of water in the sump as well. I began to notice this about 6 months ago but the car only does very short local trips these days so I haven't worried about it. But now its time to either fix it or say goodbye to the old bus. (After 415, 000ks). Apart from this problem the car is still a good runner. And its a good clean unit too. But I don't really want to spend a lot of time and money on it anymore.

I fitted new head gaskets and oil stem seals about 2 years/5000ks ago. At the same time some minor work was done on the heads to fix a coolant jacket that had corroded itself too close to the combustion zone. But I dont think that particular jacket is the problem this time. The car is not overheating and theres no bubbles in the radiator. Theres no steam or oil smoke from the exhaust either so this is purely an oil/water interface problem.

I suppose a corroded head or bad head gasket is still the most likely cause but has anyone else had this problem and suggest any other areas where oil can get into the coolant?

[RUGGA]

Auto or manual?

[alchemysa]

Auto or manual?

Auto.

[Just Cruzin]

Auto.

Could be the transmission cooler.

[RUGGA]

How old is the radiator? Bottom of radiator "could" have let go. I have never seen a NH radiator but I imagine the Trans fluid connects to the bottom of the rad like most autos. Perhaps check the auto dipstick in the morning before starting it up? This is the only other possibility of oil in rad besides internal of motor. However if you think there is water in the sump, well, you could always get your oil tested. Good luck.

[alchemysa]

How old is the radiator?

Radiator is original so its about 26 years old. I'll check in the morning but, as i recall, the tranny cooler is attached to the bottom of the radiator. I think it has a separate engine oil cooler.

The oil in the radiator is a dirty brown color. Looks more like engine oil than tranny oil to me but its hard to tell. I havent noticed anything unusual about the tranny oil but I'll check the dipsticks before and after a run tomorrow.

[Barneymutt]

Based on your explanation and my experience, it's either a cracked head or blown head gasket.

Same amount of work for both scenarios. It's a very common problem for 3Ltrs.

[stumagoo]

Based on your explanation and my experience, it's either a cracked head or blown head gasket.

Same amount of work for both scenarios. It's a very common problem for 3Ltrs.

I hate to say it but I would have to agree with this

[alchemysa]

I hate to say it but I would have to agree with this

I replaced the head gaskets and had the heads surfaced about 18 moths ago. I even went back in and retensioned them after about 1000ks. And if the head is cracked it sure isn't from being overworked, the car doesnt get used a whole lot. My guess is that corrosion in one or both of the heads is the issue. Anyway its basically all the same problem and the same amount of work to find out.

But I'm trying a cheap easy fix for now. I'm draining and thoroughly flushing the cooling system and i'm going to throw in some radiator stop leak. I've never had much luck with the stuff in the past but because this doesnt involve combustion cylinder pressures I think its worth a shot. If I get the pressure in the cooling system high enough it should pack the sealer into any cracks... at least temporarily. I shall let you know the result.

[peter54smith]

Hi there sorry to hear about your problem im having issues with my pajero shorty 1996 reg 2.8 auto 4m40. My problem was when the engine was hot fluid would flow into the overflow expansion tank, but as it cooled it was not returning into the radiator, seems to be a micro crack in the cylinder head between the water jacket and the cylinder. Repair bills in the uk would be around 1300 pounds, so i took a chance on putting in some additive to bung up the problem it worked have done approx 500 miles and its resolved the problem good luck with your cure hope it works. Best regards from uk

[tommo123]

[QUOTE=alchemysa;546371]I replaced the head gaskets and had the heads surfaced about 18 moths ago. I even went back in and retensioned them after about 1000ks.

Just out of interest did you run coolant in the engine for the first 1000ks before retensioning the head bolts?

I have read that some head gaskets can corrode if running coolant straight away.

[alchemysa]

[QUOTE=tommo123;547374]

I replaced the head gaskets and had the heads surfaced about 18 moths ago. I even went back in and retensioned them after about 1000ks.

Just out of interest did you run coolant in the engine for the first 1000ks before retensioning the head bolts?

I have read that some head gaskets can corrode if running coolant straight away.

I cant remember I'm afraid. I would imagine that I put coolant in straight away. I'm running it with stop leak at the moment. I'll go with that for a another week or two then flush it and refill with fresh water. After that I will know if its still leaking oil or not.