Possible Hgf - Oil In Coolant

[innivodave]

Hi all,

about 6 months ago I was having some trouble with my elise. It was overheating, burning water, missing under load, etc. but no visible oil in the coolant, and no visible coolant in the oil. A mate of mine was still convinced that it was HGF and was happy to do it for me, so we spent a couple of days getting the clam shell off and replaced the head gasket, along with all top end seals and a head skim and pressure test. Everything went well, the car was running great, no overheating, and the engine sounded better than it did before things started to go wrong, so I was happy that the issue was fixed.

 

A few weeks after we had put everything back together, I started to hear a kind of ticking noise coming from somewhere near the alternator, I noticed a crack in the bracket and though it was probably that, so I wasn't too worried about it. I had intended to fix it, but never found the time, and most of the time I didn't hear it, so I kept forgetting. Just thought I'd mention this in case it's related to my current issue.

 

So, a couple of weeks ago I realised that the coolant level was looking low, and didn't look pink like it usually does. I opened the cap to find the the dreaded mayonnaise like gunk on the cap and in the coolant and it had turned the coolant a dirty colour. So now I'm thinking did we do something wrong when fixing the head gasket?

 

The symptoms this time are very different from before:

Once the car has warmed up, there's nothing visible coming from the exhaust, whereas before there was a constant cloud coming from the exhaust.

There's no overheating like before, but the temperature does fluctuate - if I put my foot down, the temperature can drop from 89 into low 70s sometimes, the amount it drop depends on how hard I accelerate. I thought this may be just because the radiator was getting more air. If I'm going up a hill and stay in the gear I'm in rather than dropping down, the temp goes up slightly, only to about 91/92 tho. I did replace the temp sensor when doing the head gasket, so not sure if it's just more sensitive or if this is related to the problem?

There is definitely oil in the coolant, but no visible mixture on the oil cap.

The car seems to be running fine when driving it, but sometime take a few turns to start. Before it was missing under load.

 

I'm not driving the car any more since I've noticed this, but wondering where to go from here really. I've read some people talking about radiator or oil cooler problems causing similar symptoms, but also alot suggesting HGF. Would love to hear what you guys think about it, I'd really appreciate any ideas anyone has, particularly if there's a way of narrowing down the problem. Might be worth mentioning that it's a sport 160.

 

Thanks

Dave

[Martin R]

It does sound like HGF. As well as replacing the head gasket, you should also change the head dowels to Steel. Put a PRT on to replace the old type thermostat. Also did you check the Liner heights ? They should be 4 thou proud of the block.

[dobbo]

Have to agree with Martin - it does sound ominous.

 

You could always get confirmation - sniffer test in the expansion tank, compression test, check underneath of oil filler cap for mayo as well. If it is HGF, there's no point in further investigation - all you can do is repeat the repair !

 

The liner heights are critical on the K-series. Upgraded head gaskets and dowels sets are a no-brainer, as is a remote stat. I think the fluctuation coolant is down to an airlock rather than changes in air flow, although that's unlikely to be a cause of another HGF.

 

Couple of questions - why did you remove the clam (not relevant to HGF, just curious) ? Why was the head skimmed (if it wasn't necessary, that could have made things worse if not done correctly) ?

 

Finally (and you won't like this one), it possible that the head is porous - no HGF repair will sort that. There were some bad one - the well know K-series modifiers have stopped doing exchange heads due to the risk involved in unknowingly taking in a porous head in PX for a modified one.

[innivodave]

It does sound like HGF. As well as replacing the head gasket, you should also change the head dowels to Steel. Put a PRT on to replace the old type thermostat. Also did you check the Liner heights ? They should be 4 thou proud of the block.

 

Thanks for the quick reply Martin. The kit we used for the seals and gaskets came with stainless steel dowels, so that's all good. I'm not sure if my mate checked the liner heights, I wasn't aware if he did. What effect could it have if that wasn't checked? Does the remote thermostat make a lot of difference? I almost put one on 6 months ago but didn't do it in the end.

 

Thanks

Dave

[dobbo]

If the liner heights are correct, the gasket will not be correctly clamped when it's torqued up, so will be likely to suffer another HGF.

 

Remote stat correct a design flaw when Lotus used the K-series in a rear-wheel drive car. In a FWD car, it's fine as the loop to the radiator is short and the position of the stat isn't critical (it's on the return leg from the rad). With a RWD car, when the stat opens, there's a huge volume of cold water trying to return to the engine. With a remote stat, fitted on the out-bound leg of the coolant circuit), it gets warmer quicker and therefore opens sooner. That lets the water in the rad back to the engine earlier, so there's less temperature difference between the engine and the coolant. This reduces thermal shock to the engine block, etc, which can only be a good thing when trying to minimise distortion / warping.

 

The MGF engines also suffer from HGF, but then again, so do Landrovers - so a remote stat isn't a cure, more of a help in avoiding HGF. If you're taking it apart again, it's an easy fit. It's a complete pain to do at any other time due to the location of the existing stat.

[innivodave]

Have to agree with Martin - it does sound ominous.

 

You could always get confirmation - sniffer test in the expansion tank, compression test, check underneath of oil filler cap for mayo as well. If it is HGF, there's no point in further investigation - all you can do is repeat the repair !

 

The liner heights are critical on the K-series. Upgraded head gaskets and dowels sets are a no-brainer, as is a remote stat. I think the fluctuation coolant is down to an airlock rather than changes in air flow, although that's unlikely to be a cause of another HGF.

 

Couple of questions - why did you remove the clam (not relevant to HGF, just curious) ? Why was the head skimmed (if it wasn't necessary, that could have made things worse if not done correctly) ?

 

Finally (and you won't like this one), it possible that the head is porous - no HGF repair will sort that. There were some bad one - the well know K-series modifiers have stopped doing exchange heads due to the risk involved in unknowingly taking in a porous head in PX for a modified one.

 

Thanks for the reply Dobbo.

 

I've got a compression test kit somewhere, so I'll give that go. There's no mayo under the oil cap.

 

I'll check with my mate about the liner heights, I'm not sure if this was checked, sound like it's bad if it wasn't? I got a genuine kit from Bell and Colville, but it looked exactly like this - http://www.eliseparts.com/products/show/29...end-gasket-set/ . Wish I had just spent a bit more and got the PRT now.

 

we removed the clam just to make access easier, we did a cam belt change at the same time (was due). I was advised to skim the head while it was off, just to make sure it was flush when it went back on. Was that not the right thing to do? Is there a way of telling if the head is warped before doing that?

 

If the oil mix is dues to a porous head, would I have seen evidence of this before? When the head gasket was done before , there was no oil mixture at all, it seems to be a new thing. Also the head gasket change did fix all of the issues I had, so I'm pretty sure that was the problem before. Or have I misunderstood and you're saying that a porous head could cause the HGF?

 

Thanks

Dave

[dobbo]

Looks like we're racing each other with replies

 

Off to have to tea !

[Martin R]

I think its fair to say Dave Andrews has forgot more about the K series engine than most people will ever know. Here is a link to his website. This will keep you quiet for a bit

 

http://kengine.dvapower.com/

 

When i did my head gasket the liner heights were between 2 and 3 thou. Dave recommended using the Payen gasket if the liner heights are not perfect. Apparently you should only use the MLS gasket if the heights are all 4 thou. I also fitted a PRT. If you have the following done, ive not heard of any repeat HGF, although they may occur in rare cases.

1) Head peened, checked for hardness and skimmed. The head peening around the fire ring is to try and cure the porous casting problem.

2) Steel dowels

3) 4 thou liner heights

4) Prt fitted.

 

Head gaskets can go in a number of different ways. ie between the cylinder and oil or water ways

Just between the oil and waterways and also between cylinders and nothing else.

HTH