Thread: Up date on TD5 headgasket change

Originally Posted by robert42

Hi All, To answer cjcTd5 about 2mm as the dowl was nealy cut in two..I could see shiney Ally on the gasket from where the head had moved around..I asked all around and it seems that putting steel dowls back could risk the block .. when the head moves NEXT time?? it could blow the side out where the dowls are fitted...The guy thats doing the job is right there with the latest info.. As soon as I said I would like steel dowls put in he just smiled and explained what would be the out come down the track..There is not a lot of metal near the outer side of the block when this is pointed out..The guy is in his 60,s and has been at this all his life. Has the big A hanging in the work shop..How could I say otherwise..This is not his first td5 head..number 7??.. others had the dowls cut in half, he said I was lucky to stop when I did..thats y I waited two weeks. for him to do the job. Hope I havent frightened anyone...I thought steel would stop the head moving but there is to much pressure and some thing has to give, he said.. It will last a life time just driving around town, but pulling a 20ft. van is another thing...Might have to down size the van..tent maybe ...Smile they are made to use....And dam nice to ride in, In a weak moment I sat in the new v8 toejo.MMM, not good..Wife said we are not going backwards,so forget that idea. If I have to do this every 150thou. so be it...The ride is worth it....No I dont like LAND ROVERS.. just love them...Dollar for Dollar.. the best.. Carnt wait to get my 3 ser. Next year maybe..Thanks ,robert42

Thankyou.....

Now maybe we can stop these rumours re plastic dowels

It's ALL to do with losing tension in the bolts on the head...
Steel dowels only mask the issue.... Problems are still happening at this point.

Thanks Tombraider at last something that sounds logical and will be well worth investigating.
Just cant understand how the plastic dowels used to hold a head gasket during installation cause failures.

I wonder if it's possible to convert to head studs instead of one use bolts?
Maybe some grade 8 studs would be less likely to stretch. Anyone know if it's a likely possibility to fit them?

that would have to be the worlds longest stud... and the bolts are a grade 10 to start with Id be thinking that the grade 8s would stretch with the heat.

Since it is conclusive that the head bolts are losing tension and it is not the plastic dowels would there be any advantage to increase the torqueing down the head?

I had a race car once that was supectable to blowing head gaskets. The fix was to increase the Nm by 10%. This fixed my problem and never had a head gasket failure again.

Maybe something to consider when my head gasket blows I would be replacing all head bolts which you have to do anyway but I would increase the Nm.

Except they aren't done up to a Nm figure. They are single use stretch bolts done up by degrees.

Trust me, if you haven't done one, the tension is tight, tight, f...n tight .

so whats the go with this BigJon??

is it overheating?
"soft" bolts?
bad assembly?

The ones I have seen... overheating.

Poor maintenance causing hose failure. Often the small one behind the turbo. Top radiator hose is another common one.