Overheating and bleeding

[phedders]

I nearly got old trying to read previous threads on cooling etc.

Anway - been having problems with my Bongo overheating. (Mason and Haydn alarms both fitted and working. So no cracked head...)

But anyway. The garage I took it too a few weeks back (who really know their bongos) found a leaky pipe - replaced it and spent two days trying to bleed it. (I had previously found it very hard too.)

All fine until a few days ago... and the sitting is traffic for 25 minutes or so on a cold morning and the temp gauge rises quickly... and I stop.

A little coolant overflow - replaced it. Waited and finished my journey. Lunchtime - I nipped into Tesco and bought a funnel and a bucket. Tried the seesaw again. Spent over 60 minutes with the engine running getting burps _continuously_ Why?!

After work I started driving home - the non-motorway/slower but shorter route. After about 7 miles - overheating...

So I grabbed the bucket and (very carefully!!!) opened the bleed hose - Got a mix of high pressure water squirting out, and very large noisy and hot steam burps. Or were they explosions. Very impressive amounts of air. Kept going till the pressure had died right down and pushed the plug right back in. Put the expelled coolant into the expansion tank.

No problems since!

I am certain that the problems are all bleed related, and it seems that waiting till the engine was really hot - and the system well pressurised - then bleeding allowed the pressure in the tank to push the remaining air in the head out of the bleed very effectively.

NB:
I had spoken to the garage and they mentioned that air primarily gets trapped in the head, the top hose/rad and the bottom hose. Now the ball valve in the thermostat should deal with air in the bottom hose hif you give that hose a good mashing - but you may have to do that whilst the car is in a nose down attitude since the BH goes up and over the axyl. As to the TH/rad he said to lower the amount of fluid in the system to bellow the rad cap - then remove the rad cap and mash the TH until you see the burps come out of the rad - than fill into the rad cap until it is brimming - fit the cap, then fill the expansion tank - and _then_ bleed the head.

What a pain!!!

And since it may be relevant - measured my bottom hose at 35deg with top at 68 after some town driving on Sat. So the rad/thermostat are apparently both working. (Although with the BH at 35 perhaps the rad is not being used evenly and should be replaced - must check that - and can do now I have an IR thermometer...)

Any thoughts anyone?

[haydn callow]

You seem to have done everything right...really sounds to me that with all that high pressure burping you may have cooked the head gasket....get a gas test done on the expansion tank...I would guess your radiator is doing it's job o.k.

[phedders]

Both the AA and the garage have done carbon tests on the fluid... and say it's fine... and the garage did overnight pressure tests too.