coolant pressurising please help!!!

[bigdan]

hi had my bongo for two years now and hasn't been working for most of it some of which is my fault.
so bought the bongo with an over heating problem found another engine on Ebay had it fitted worked fine till it dropped a valve and smashed the head and piston.
so i saved up again had the original engine stripped head tested new valve fitted all tested fine
after replacing the only steel bit on the head the bit that the hoses connect to it on the passengers side as it was leaking. put the engine back in the van started and works fine but the coolant is pressurising if i tighten the filler cap after about 30 seconds the engine starts to run lumpy release the pressure from the expansion tank and it runs fine again but doesn't seem to over heat and the rear heaters don't seem to get very warm but I don't know if they ever have since I've owned it does this mean the head or gasket have failed or could it be something less costly?
thanks Danny

[Harry]

Either of three possibilities spring to mind.

1. Best scenario....the system has an air lock somewhere and needs bleeding properly. If the thermostat is sticking then this can cause difficulty in getting a proper bleed. There is a factsheet on bleeding in the members area.

2. The head gasket has gone....but if you are removing the head to replace it then get new stretch bolts too...and get the head checked/skimmed/pressure tested at the same time.

3. The head is cracked.....

good luck

H

[Trouble at t'Mill]

Bigdan, I agree with Harry.

How quickly does it happen after you fire her up from cold? If it's within a couple of minutes, I'd suspect a leaking head gasket (the cylinder compression is passing into the coolant chambers) or even cracked (tho' surely you'd have known about this before fitting?)

If it needs to at least partially warm up first, then the above could still be the cause, but I guess it could also be localised overheating due to an air-lock or similar.

[stilldesperate]

Hi Bigdan,

Can you get it to the local MOT centre? They can use the exhaust gas analyser to test the head, quick and pretty accurate, afaik.

SD

[bigdan]

thanks for that i will get it to the MOT station
it starts pressurising as soon as i start it
if the head was porous would this not have shown up when it was pressure tested?
could the block be cracked have you ever heard of this on bongos before as the engine was over heating when i got it and i didn't get any history of how bad ect.

Thanks Again
Danny

[francophile1947]

A cracked block is not unknown, but thankfully rare.
Don't forget to put your location in your profile - it helps us to help you

[bigdan]

is there a bongo specialists local to me in Southport?

[daveblueozzie]

dont know of any in Southport ,but there is Wheelquick at Wigan. outstanding reputation for anything bongos .

Wheelquick
85 Enfield Street
WN5 8DJ Wigan

Phone:
08446631920

[bongoing-mad-simon]

Hi bigdan , unfortunatley the blocks do crack as i found out ,after having a new head ,rad ,waterpump,thermostat and spending over £1500, my bongo continued to pressurise and blow out it's coolant , later found this out to being caused by a crack in the cylinder water jacket, causing a pump effect pressurization. If I was in the same predicament again I would bite the bullet and buy a replacement engine from a reputable company . Good luck with getting yours sorted heres hoping its something simple .

[The Great Pretender]

When the head was pressure tested did you also check it wasn't warped?