Series 3 New head gasket failed!

Harrris303 · Oct 12, 2020

Hi everyone. So getting on for a year ago I realised the head gasket had gone on my 2.25 petrol, and did the replacement myself, which was a first so it may well be my fault that it's gone wrong, but I thought I'd followed the correct procedure to the letter.

It's been off the road since then so the engine's not been run very much at all in the meantime, and I hadn't had a chance to fire it up for maybe a couple of months until yesterday. So I got it started but it was running horribly and kicking out all sorts of smoke. I randomly checked the oil level and it was way above what it should be, and I quickly realised that could only because water had leaked in from the cooling system!! Which was confirmed as the oil felt very thin, and the radiator was pretty low. So bloody disaster basically.

I've drained the oil and the coolant, and I'm planning on refilling the oil tonight and running it for a little while to hopefully burn out any of the water that's left in there, whilst obviously not letting it overheat. Does this sound sensible at all?

And then I guess I'll replace the head gasket again, but I'm obviously dreading the same thing happening again... I had the head skimmed and reconditioned when it was off, so I don't know if it might mean the block is warped? The only other possibility I can think of is that I might not have got round to retightening the head bolts after I'd run the new gasket in. I know that's what you're supposed to do but not sure how likely that is to be the problem?

As usual any input would be much appreciated! Cheers.

tottot · Oct 12, 2020

Doubt it is a warped block. Could be internal corrosion if engine had no anti freeze/inhibitor for years. Having sat for a long time it would only have to be a small leak. Could be just a duff gasket.
I recon the best next move is to remove the head again and carefully check for a sign of a tracking leak on the gasket head and block. I would not waste oil just to do a short run.
Others on here may have more ideas.

kermit_rr · Oct 12, 2020

You said the oil was very thin. Does it smell of petrol?
I'm sure there's a possibility of the mechanical fuel pump leaking into the sump

tottot · Oct 12, 2020

Have you still got the oil you drained ? Put in a clear container and water will soon settle out.

Harrris303 · Oct 12, 2020

kermit_rr said:
You said the oil was very thin. Does it smell of petrol?
I'm sure there's a possibility of the mechanical fuel pump leaking into the sump

I hadn't thought of that actually, although I didn't notice a particular smell of petrol. Would it be possible for petrol to continue leaking for a long time or would it just be the fuel in the pump? As the oil level was massively raised so whatever the liquid was there was a lot of it. It did strike me as odd that it seemed quite well-mixed with the oil though instead of separating like I'd imagine water would.

tottot said:
Doubt it is a warped block. Could be internal corrosion if engine had no anti freeze/inhibitor for years. Having sat for a long time it would only have to be a small leak. Could be just a duff gasket.
I recon the best next move is to remove the head again and carefully check for a sign of a tracking leak on the gasket head and block. I would not waste oil just to do a short run.
Others on here may have more ideas.

I'm glad to hear you don't think it's be a warped block. Yes I was planning on trying to get the head back off really carefully and see if I could see any clues as to where the leak was. Thanks for your input.

Harrris303 · Oct 12, 2020

tottot said:
Have you still got the oil you drained ? Put in a clear container and water will soon settle out.

Yes still got the oil so I'll give that a try. I certainly didn't see any evidence of separated water so maybe it is fuel after all...

kermit_rr · Oct 12, 2020

Water in the oil goes milky and claggy very quick once the engine is running.
Fuel should only get into the sump while the engine is running, pretty sure it can't syphon unless you're parked at a good angle

kermit_rr · Oct 12, 2020

You can manually operated the pump with the lever. Once the carb is full you should feel the pump operation change. If it keeps pumping then the fuel is going elsewhere

Harrris303 · Oct 12, 2020

Yeah she's been parked on the flat and not been running except when I ran her yesterday for a little while. Well I've drained all the water out so I guess maybe I could refill the oil until it reads on the dipstick and then try manually pumping some fuel to see if that affects the oil level. Certainly going to try that before taking the head off again in that case!

Harrris303 · Oct 12, 2020

kermit_rr said:
Water in the oil goes milky and claggy very quick once the engine is running.
Fuel should only get into the sump while the engine is running, pretty sure it can't syphon unless you're parked at a good angle

Yes I was imagining I'd see the classic 'mayonnaise' thing too but didn't see much sign of anything like that.

Harrris303 · Oct 12, 2020

Thanks for the input guys. Good to have some kind of starting point. Saves me crying into a pint just yet!

Colthebrummie · Oct 12, 2020

When you replaced the head gasket, did you replace it with a composite one? Have you checked the torque of the head bolts sin Everyday?

Col

kermit_rr · Oct 12, 2020

Remember series head bolts aren't the modern stretch type so need retightening after a few 100 miles

Colthebrummie · Oct 12, 2020

Sorry about the last bit of my last post, have read it, even I don't understand it. It was supposed to say, have you checked the torque of the head bolts since replacing the head gasket.

Col

Henry_b · Oct 12, 2020

If the headbolts are finger tight i'd say thats your issue LOL

rob1miles · Oct 12, 2020

As siad above, it could be an existing fault that was masked by the head gasket problem. It could be (like the fuel pump) quite unrelated but perhaps due to standing or being disturbed. If its is the head gasket then it may be obvious like a duff gasket, or not like studs that are too long. Take your time checking before you take the head off again. Can you check the compression? If its OK then look elsewhere first, if its not then go straight for the head. As above - draining the oil will tell you a lot. Many years ago I changed the head gasket on a Jaguar - a heafty job. When to a road test and it lost its water. Checked the oil and found the water. Checked compression - OK ? Took the rocker covers off, got a torch and found a hole corroded through the water pump into the cam chain cover. I must have distrubed it and one tiny part was paper thin. Drilled out the corrosion and pegged it.

Harrris303 · Oct 13, 2020

Well... last night I managed to find a couple of demijohns to pour the oil into and actually couldn't see any evidence of water in it at all! I even poured a bit of water into one of them to see how it behaved and there's definitely no mistaking it, so I think it is indeed petrol in the oil. Sadly the big can I originally poured it into had previously contained petrol so it was hard to tell if the oil smelled of petrol as that was all I could smell haha. But I think it does!

One thing I did notice when I got it running the other day was that the engine ran better when it first started and got worse, which I was thinking could imply the fuel was pumped in with the oil once it was running rather than seeping in over time. I also noticed that however much I depressed the throttle it didn't really affect the revs, which again could imply the fuel was going somewhere it shouldn't. (It was running so horribly that I forgot about the throttle thing pretty quickly!) So would we say the pump is the first thing to check?

Thanks for all the added info on the head gasket. As I mentioned it hasn't been run very much at all since being changed but I'll be sure to check the tightness of the bolts, and actually as mentioned in the previous post I'll do a compression test this morning to be sure. I hadn't even thought of a compression test as I was just assuming it must be the head gasket from the start.

Colthebrummie · Oct 13, 2020

I doubt the problem is the fuel pump, if it was leaking petrol into the sump fast enough for the oil level to raise significantly, I would doubt that the engine would start at all. Is there a transparent fuel filter fitted, if so, how much fuel is in it. When you replaced the head, did you check the tappets?

Col

Harrris303 · Oct 13, 2020

Annoyingly I won't be able to get back to the Landy til Thurs now to check the fuel level in the filter, but it does have a transparent one so I'll check that.

Sadly the head gasket was a fairly big learning curve for me as it was so I didn't dare delve any deeper, but maybe I should've by the sound of it?

rob1miles · Oct 13, 2020

Could it be a stuck float flooding the engine? I'm not familiar with the carbs (mine's diesel)

Series 3 New head gasket failed!

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Think outside, no box required.

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