Vacuum bleeding coolant

[tobongoornot]

Hi there,

Quick question with regards bleeding the air out of the Bongo coolant system. My Bongo is in the garage due to coolant loss and the garage have used a vacuum kit or pump or whatever it is to bleed the system but it's still behaving like it has an air lock in the system(Bongo idles fine, runs up to full temp, thermostat opens, fans kick in but as soon as it's put under load or run over 3000 revs blows a load of water out of the expansion tank and the temperature needle goes through the roof).

So my question is are these devices reliable for clearing air locks from the Bongo or should they stick to the methods in the fact sheets?

Cheers,
Rob.

[Doone]

Hubby has bled literally dozens and dozens of these. No special tools are required. I'm assuming that they've fixed what caused the coolant loss. Have you seen the amendment to the factsheet suggested by dandywarhol? It may help.

"The bleed hose can be found under the passenger seat
*Set the hose in a downward position higher than the coolant level in the expansion tank" etc.....................

This is what the Factory manual is showing when the picture of the bleed hose is hanging from the steering wheel, otherwise the colant will just syphon out to the expansion tank until it's found it's level at the hose. But if you set the bleed hose LOWER than anywhere else in the system an airlock could occur.

I've bled several systems EXACTLY by the book and had no problems - the whole procedure can be over in about 20 mins.

[haydn callow]

I would say if it has done this several times you have a bigger problem than just a air lock.
Even using a vacuum pump I'm not sure it would bleed a Bongo system without opening the bleed hose and submerging it in a bucket of coolant.
I would do it the hard way and get the stat open. If the temp is going through the roof I suspect the worst. Was it overheating before the garage got hold of it |??
Is the garage well up on Bongo cooling systems ??

[teenmal]

Hi Rob Do you know what caused the leak?

Mal..

[tobongoornot]

Thanks for the responses.

The whole story behind the episode is I had a coolant leak which I picked up due to the coolant loss alarm before leaving work for home last week. I had the AA out who could not find a leak. They did some sort of pressure test with a pump on the expansion tank and no leak. So we topped the system up and ran it but could not get it to stop blowing coolant from the expansion tank under load so it was recovered to my local garage.

They have done the following

1) Bled the system using some sort of vacuum pump.
2) Put a chemical in the coolant to test for exhaust gases(none found)
3) Checked the water pump which seems ok.

The only other thing I was able to suggest to them is to check the flow through the rad.

I'm wondering if the leak may be coming from the pipe that runs to the thermostat as the original pressure test was with a cool engine.

[mikeonb4c]

What about Haydn's experience with the bottom hose collapsing. I wonder if yours might do that when revved. Did the old coolant look cruddy/rusty. I'm deeply interested in ways of identifying if their is a poor circulation issue. Defo. flowtest the radiator I think.

Good luck & keep us posted

Mike

[Harry]

Try reading my post: 'A day of Highs and Lows' in the bongo chat section....sounds familiar????

H

[tobongoornot]

Thanks again for the responses, in answer to the rust question yes my bongo does suffer from rust in the coolant which is why I suggested they check the flow through the rad. I will suggest they keep an eye on the lower pipe when testing.

[tobongoornot]

Well a weekend of trying to blead the bongo and no change.

It's fine when stationary runs up to temp thermostat opens fans kick in but as soon as it's put under load it overheats and kicks loads of coolant out of the expansion tank. It seems like it can sit there forever and a day on idle but as soon as you give it some revs it over heats.

They have pressure tested the coolant system and can't find any leak. The test foe exhaust gases also comes back negative. All the hoses look ok.

Can anyone else suggest anything or is it time to accept I have a serious issue and get the garage to strip it down and check for a cracked head or blown gasket?

[bigdaddycain]

I have never yet heard of a sniffer test to be wrong. Just so long as the test is done properly of course.

Do you have a good strong, steady heat from both heaters when up to temp?

[tobongoornot]

Not 100% sure about the rear heater but the front heater is spot on.

Would the sniffer test fail on with a cracked head as well?

I just checked with the garage and they have not done a flow test on the rad yet so they will do that next. I have spotted a cheap second hand rad on ebay might take a risk and get it on accounts of the rust in my coolant.

[tobongoornot]

Update on how I'm getting on it's a bit of a horror story I'm afraid.

To re-cap original fault was loss of coolant which caused the Bongo to overheat.

After a faulty coolant hose was replaced when tested the gauge would sit at the 11 o'clock position fine right up until you rev the engine or take it on a run. Then it would flip right over to the right hand side and coolant would blow out of the expansion tank.

The head gasket and cylinder head seemed ok (passed a sniffer test) Due to rusty coolant the radiator and thermostat were changed. Re-filled the system ran it up to temp and all looked good. They the test drove it about 10 miles and all looked ok but then it started overheating all of the time again. Garage then diagnosed as cylinder head fault which has been replaced.

Car is no longer overheating as much instead of flipping all the way over the needle gets to about the 2 o'clock position and remains there.

Asked them to check heat from the heaters and the front was fine but no heat out of the rear(which I’m pretty sure was fine on day 1 of the fault). They have removed the rear heater matrix which is full of sludge.

Latest is they will bypass the matrix and see if the problem clears up.

Either way I guess I’m better off replacing the rear heater matrix.

[waycar8]

plenty of second hand ones on ebay, give the breakers a call, glad you seem to have finally sourced the problem