4Runner cooling

[Tiff]

Hi, my name is Tiff and I have a problem with my 1993 4Runner 3ltr TD ( KZN 130 engine ).
Even from cold, the coolant is being blown out at higher revs. The coolant tested positive for exaust gasses.
Prior to having this problem, a new radiator had been fitted. I have now fitted a new cylinder head ( old one cracked ), new thermostat and checked the water pump for wear and hoses for obstructions (all ok).
On the first test run, going up a steep hill at highish revs, the water suddenly blew out and I ended up with the new head warping.This was then refaced. On re assembly with more new gaskets, I still have the same problem. The head was again removed and crack tested, proved ok. As far as I can tell at the moment, the bores do not appear to have cracked and the top of the block is not warped or cracked.
As the turbo has a water cooled bearing, is it possible for the exaust gasses to get into the cooling system via this?
Any ideas will be appreciated, Tiff Amsdon

[That Ruddy Squirrel]

Hi Tiff and welcome to the forum.

Can I ask where did you get the head from ?

Some members here have suffered when they get heads from fleabay.

The best place to get one is Stevo at the Engine Co Ltd.


Trev

[Tiff]

Hi UDTrev, Bought a fully built up head from Milner Off Road, Tiff

[Tallyman]

Quick question is who did the engine re-build, you or a garage? If it's a garage, then send it back and tell them to put it right. If you did it yourself, did you use new head bolts and torque it down correctly? Toyota head bolts are designed to stretch when torqued down and really should be replaced with new whenever the head is removed/replaced, otherwise they might not be holding the head down at the correct torque.

I also believe I saw somewhere that there are different thicknesses of head gasket (but could be wrong on that) which might make a difference. Also, did you make sure you fully burped the cooling system before running it a high revs? You need to ensure that both the front and rear heaters (if you have both) are fully open when refilling the coolant and you should run the engine with the rad cap off for a while to get as much air out of the system before presurising it. Could be the rad overflowed because of excess air in the system, rather than another problem with the head.