Cylinder head gasket leak

[Gizmops]

Hi, I purchased the HDJ80 a couple of months ago and a few weeks later noticed a water loss. The garage in Spain were unable to trace it. I have just done a coolant pressure test and found a leak at the rear of the cylinder head. Should the cylinder head have been retourqed, what is the setting please

 

[Gizmops]

Waiting information as to when the head gasket was changed.

 

[frank rabbets]

If you go to "Resources" at the top of this page you will probably find a workshop manual for your engine. I had a loose cylinder head on a diesel land Rover once. Tightening the head bolts permanently cured it.

 

[Dave2000]

Hi, I live and work in Spain as a mechanic, temporarily on sick leave. But to answer your question the answer is no need to retorque the head, the bolts (should have been new) stretch and maintain a clamping force as the gasket settles. Fitting a head as heavy as that in the 80 is not easy without damaging the gasket or faces, the correct way is simple enough if know you what you are doing.

You don't say if the garage changed the gasket, if so take it back? Other points to note is the head should have been skimmed, and the gasket thickness chosen to suit the amount skimmed off, piston at TDC over block height and so forth.

Regards

Dave

 

[Gizmops]

Hi, i cant get information from the previous owner when gasket was done so it is going to have to come off again and skimmed if needed. Tried to get a manual as per advice from Frank , got charged to do a search and didnt find one. Stumped for now.

 

[frank rabbets]

Is it Diesel or Petrol. And what year? If the bolts are loose you could try tightening them. I did not replace the bolts on mine after refitting the head. I'll send you the figures.

 

[Gizmops]

Hi Frank its a 4.2 diesel 1hdt

 

[Gizmops]

Its a 1992 12v

 

[Gizmops]

Hello Dave2000, i live near Gandia, Valencia, may i ask where you are. I am also a retired mechanic, old school pre electronics which is why i bought the hdj80.
Regards

 

[Dave2000]

I am on the Murcia/Almeria border near the coast, so a good four hour drive over.

Regards

Dave

 

[Dave2000]

Is it Diesel or Petrol. And what year? If the bolts are loose you could try tightening them. I did not replace the bolts on mine after refitting the head. I'll send you the figures.

You got lucky then Frank, they are brought to a torque setting and then you use a dial gauge to bring them to tension, they should be replaced with new when replacing the head.

If I was going to do anything with the OP problem I would purchase a new set of bolts and replace one at a time using the correct torque and the rotation degrees. Yes technically a tad naughty but may solve the issue? Applying tension to a used bolt could result in a breakage, and the possibility of having to remove the head to get the broken portion out of the block.

Regards

Dave

 

[frank rabbets]

I followed the procedure in the T WSM Dave. It does not say to replace bolts, only if deformed or broken. It is most important before installing the bolts to clean ever bolt hole with forceps and cloth to remove any excess oil otherwise hydraulic compression might split the block when tightening the bolts. You can also use your old big end bolts as long as they measure to spec on WSM.

 

[frank rabbets]

Photo as above in case PDF does not open but it opens OK on my computer.

 

[Gizmops]

Many thanks Frank, i will try and give it a go tomorrow.

 

[frank rabbets]

24 Valve instructions posted by mistake. The following are very slightly different for 12 valve. Let me know PDFs open OK.

 

[Gizmops]

Thanks Frank downloaded ok on my phone, i will try and print them out.

 

[Dave2000]

Your absolutely right Frank, and of course you can measure and make a judgement call but is it really worth it, given the work and risk? Also there is something else, Toyota do say you can measure them, followed by........if some twist or break you should replace them. Did Toyota base those calculations based on an engine that the bolts had gone through thousands of hot/cold cycles on a 30 plus year old engine? Of course not, they based it on current knowledge at the time, the huge number of big end failures prove my point.

What if when the head gasket was done and the old bolts were reused, if so have they become loose? If not loose why has the gasket failed again? Then the part about over oiling the threads absolutely correct again, if the bolts have come loose oil will undoubtedly have worked it's way down the threads and pooled below the bolts this brings back another 'what if' of the possibility of hydraulic damage, perhaps the person who did the gasket was a carpenter?

Perhaps my work ethic as a mechanic is a little strict, but I am good with that.

Regards

Dave