overheating problem

[bongo al]

Continued from this thread - http://www.igmaynard.co.uk/bongo/forum/ ... =3&t=33562

Thanks to all who responded to the previous thread. Our Bongo has been in the garage for some weeks now, but still will not run properly. It still gets hot, starts to bubble and ejects coolant. Here is what happened.

Since our last post, our local garage has removed and flow tested the radiator. No problems there. Having already replaced a leaky water pump, and replaced the stat and gasket as a precaution, we were left with the conclusion it must be a problem with the head / head gasket. Off came the head and away it went to be pressure tested for cracks and to be skimmed. Great news! Nothing wrong with the head. Trouble was, the old head gasket did not look that bad. Hard to see any evidence of where it might have failed. Anyway, the garage fitted it all back up and carefully bled the system, a job they are getting quite expert at!

Same old bubbling and steaming. They took out the stat. No improvement. The top hose gets warm, but the lower hose refuses to. They persevered with trying to bleed the system and were rewarded with a lower hose being blown off!

All this pressure must be coming from somewhere. The Garage feels there must be a crack in the block. Ouch! and Double OUCH!

Can anyone help with anything obvious we are missing?

Thanks in advance

Al

[dandywarhol]

check out the current thread about using spurious gaskets.

http://www.igmaynard.co.uk/bongo/forum/ ... =3&t=34506

[missfixit70]

When they tested the head, did they do so under normal working temperature?

[Simon Jones]

Had similar problem myself. The chances of it being a cracked block are very slim. I've only met one person who has actually found this had happened.

These are my comments from a previous post:

I had head gasket failure & I had the head tested & skimmed, but when I reassembled it water was still being blown out the expansion tank. After speaking to a well-known Bongo garage, they gave me two invaluable tips:

Deck the block. This is where you use very fine abrasive on a granite slab to remove any high spots from the top of the cast iron block. There is no point in fitting a perfectly flat new head to a block that is uneven.

Use Wellseal gasket sealant. Although sealant on gaskets is not generally the 'done thing' these days, it gives the best chance of a pressure-tight seal.

I've mentioned both these points on a few occasions, but its worth bearing them in mind as they really can make the difference between a quick fix & a long term solution.

[bongo al]

Hi Guys. Back again. (Thanks by the way to MissFixit for linking to the previous thread - I did not know how to do that!)

I printed off your previous posts and handed to the mechanic today. I was curious about the head gasket. He said he fitted a 'payen' gasket which we both would normally consider to be a good brand. Anyone any experience with these? He did comment it was considerably cheaper than prices indicated in some of the posts.

The bongo is 'back together' and can be moved, but not far. The mechanic says it starts blowing bubbles even before it gets hot, so he believes the excess pressure comes from combustion gases, not from steam in hot coolant.

Also gave him the number of a specialist in Market Drayton from the club database, but he says he keeps getting a 'please try later' message everytime he rings.

Thanks in advance

Al

[bongo al]

Well! Busy and expensive time just recently!

Off came the head - skimmed - pressure tested perfect!
Back on, same old overheating. Tried some steel seal and left the stat out. Now we don't get warm at all. drove around for 2 weeks without a hitch. Even on the motorway it stayed in the cold.

Bought a new stat and fitted it. It will idle for an hour with no problem BUT drive it up the road again and it gets very hot.

Any good ideas, bongonauts?

Regards

AL

[The Great Pretender]

Do both heaters get to operating temp?

[mikeonb4c]

What about water pump and radiator. Poor performance from either of those could cause it (have caused it originally? - sorry havent re-read thread).

[bongo al]

Sorry for my delay in replying. I was waiting to get our bongo back from the garage, which finally happened today. Coming home a distance of about 3 miles along a county lane at around 45 -50 mph, the engine eventualy got up to normal temperature. The rear heater gets hot, but the front one only gets lukewarm. So far so good, so i decided to go on to our local ASDA. This journey was a bit faster, and longer, and at its end i noticed the needle was now past normal at the 1 o'clock position. I parked up for about an hour to let it cool. On my return, I started the engine and noted the needle was now slightly below normal, so i decided it was safe to drive home, doing so at a sedate 45 -50 mph. The needle stayed at normal on the main road, only rising slightly when i pulled off into our road, goiing uphill for about 1/4 mile to our house. However, I did note the radiator fans were on when i switched off then on again.
All of this was reported back to the mechanic, whose best offer was to try bleeding the cooling system yet again! Obviously we have missed our vehicle for the late summer, It would be nice to have it right for the spring! Does anyone know a good bongo mechanic in Shropshire??

Regards

Al

[mikeonb4c]

Sorry for my delay in replying. I was waiting to get our bongo back from the garage, which finally happened today. Coming home a distance of about 3 miles along a county lane at around 45 -50 mph, the engine eventualy got up to normal temperature. The rear heater gets hot, but the front one only gets lukewarm. So far so good, so i decided to go on to our local ASDA. This journey was a bit faster, and longer, and at its end i noticed the needle was now past normal at the 1 o'clock position. I parked up for about an hour to let it cool. On my return, I started the engine and noted the needle was now slightly below normal, so i decided it was safe to drive home, doing so at a sedate 45 -50 mph. The needle stayed at normal on the main road, only rising slightly when i pulled off into our road, goiing uphill for about 1/4 mile to our house. However, I did note the radiator fans were on when i switched off then on again.
All of this was reported back to the mechanic, whose best offer was to try bleeding the cooling system yet again! Obviously we have missed our vehicle for the late summer, It would be nice to have it right for the spring! Does anyone know a good bongo mechanic in Shropshire??

Regards

Al

Ian Taylor at Market Drayton is well recognised as an expert in the Bongo world. Have you tried him?