recently succumbed to the cylinder head problem, local diesel specialist motor engineers fitted recond head new valves etc, also changed cam belt while doing job, all seemed ok , but after doing about 50 miles same prob. they are investigating possible air lock (no luck when i last talked to them), does anyone know if there is a way to bleed the system? also the mechanic said he can leave the bus idling all day no problems but when he increases revs the coolant overflows into the expansion tank, he wanders if the rad cap is correct (6psi) his nissan patrol has a 15psi cap.
he admits he is clutching at straws at the moment. any ideas anyone?

- (#7096) Ronnie Coe, 6 Feb 03

ronnie, the cap is rated at 0.9 of a bar (a bar being 14.7 pouns @ sea level). so you got the wrong cap!. you must get the correct cap , and if i were you id get it from toyota in this case as the pattern ones eat the rubber rings due to the heat. ask the garage if they checked the horizontal drillings between the cylinders for blockages , all the ones ive seen have been full of that chemical formulae sh(1)t . fill the rads up slow and the new cap lends itself to self bleeding anyways - thats why its over a tenner i guess
jim
- (#7097) j adgo, 6 Feb 03

thanks Jim, i'll let the garage know 1st thing, maybe save them some work,

- (#7098) Ronnie Coe, 6 Feb 03

reving the engine with the cap off CAN result in overflow, even with a good system. However, no pressure should be evident- it's just caused by the flow from the water pump. A pressure test is what's needed. If the engine is started, no pressure should build up in the system until at full operating temp.

It's essential that the Toyota cap is used. Not just is it the correct pressure and self- bleeding, but it's also built to withstand the temperatures attained in the townie. The cheapie caps' springs loose tension and the seals become brittle in no time at all.

- (#7099) david miller, 6 Feb 03

was cap purchased from toyota dealer but its only 6psi
dealer said it was correct for townace....what is correct 6 or 15 psi
- (#7100) Ronnie Coe, 6 Feb 03

I think you're misreading the cap- it's 0.9, not 6.0...
but more seriously, was it the specific townace cap? should have a big brown loose fitting valve in the middle (plastic), not the usual small brass disc. The dealer may have assumed that the standard Denso cap fits all...

- (#7101) david miller, 7 Feb 03

correct david, mechanic had missread the 9 for a 6, so back to square one i suppose :(
- (#7102) Ronnie Coe, 7 Feb 03

Ronnie, Make sure they change the stat too - THe stats not as critical in aftermarket form as the rad cap, however concensus again leads us belive it has a better broad range of performance and is more consistant than the pattern ones. toyota part number is 90916 03046 - it has an opening of 30mm x 10mm as oppose to aftermarket ones which are usually 25mmx8mm
the latest rad cap by the way is 16401-64501 ( uses a float arrangement to ensure no air locks and collapsed hoses result)
check the viscous coupling too on the fan side it can fail .. drive with the seat up ..and see if its spinning ( u can tie some cotton to it and it should snap it it when it gets warm if its ok - not the best method of testing though)
jim

- (#7103) J Adgo, 9 Feb 03

Forgot to mention, first get a radiator pressure test to see if the head gasget and head are sound
jim

- (#7104) J adgo, 9 Feb 03

car still off the road, garage scratching their heads, supplier of the head insists it is ok, garage are guessing that it may be the block that is cracked as well , but the engine runs well without any water coming out of the exhaust... but shows signs of pressure in the cooling system,, bubbles when rad cap is off, seem reluctant to take off the head again as it is such a long job

- (#7173) Ronnie Coe, 13 Feb 03

try the stuff i told the site about called seal up liquid glass i used it just after xmas and it's still ok that may get you mobile till you can sort it out

hth ian

- (#7174) ian, 13 Feb 03

Is the rad cap I have unusual?
92-2ct liteace. Its not a brass or rubber seal. I recon its a ceramic type seal ( it neither feels metallic or plastic/rubbery )It has all the usual jap writing on the cover and the seal is about 3-4mm thick! Also its a tricky fit- very difficult to open if there's any, even minimal, residual heat in the engine ( the cap slackens but requires a lot of rocking to remove ). I have'nt been following most of the overheating threads, as it has'nt happened to me yet ( I'm still waiting with nervous anticipation.
Any comments?

- (#7254) stephen judge, 15 Feb 03

no, Stephen, sounds normal. The plastic bit is hard and brown, not unlike a ceramic.

- (#7255) david miller, 16 Feb 03