Compression test low, unable to bleed and overheat.

[Weeduggy]

Just spent 10 weeks offshore and come back to a very poorly bongo.

While away my wife informed me a hose burst and the temp gauge went to fully hot. I'm not sure how long she drove it for while overheating but she took it to a local garage who replaced the hose but they couldn't get It to bleed properly. As it stands now they have checked the thermostat and it's fine, They have done a compression test and it's down on two of four of the cylinders and they seem to think its pointing to the head gasket. Hot gases entering the water causing air locks and subsequently overheating. The mechanic tells me he looked at the vids on you tube about bleeding but can't get it to work. You can start it up and the temp will be fine while it idles but as soon as you drive it 500 yards the gauge goes through the roof and then when it cools down the header tank is empty.

Hopefully someone out there can throw some light on this.

Thanks in advance

[francophile1947]

It definitely sounds like the head gasket or even the cylinder head. Sadly the heads are prone to cracking if the van is driven whilst overheating

[Peg leg Pete]

If any air is getting into cooling system, it will not bleed! Agree with Francophile

[Northern Bongolow]

ask the garage to do a pressure test on the coolant system, if they put 1bar of pressure in the system, see if it holds the pressure for a few mins, if not it may have leak somewhere that needs fixing before it will bleed ok.
if the system is holding pressure it could be that the head has cracked, this could explain the odd readings on 2 of the cylinders. which cylinders are reading low, is it the middle ????. when the heads crack they usually go around the exhaust valves/seats.

[Weeduggy]

Cheers guys,

Think you've confirmed what I was hoping wouldn't be true.

It's the middle two cylinders that are down by a about 1/3 and 1/4 of what they should be. If the head cracks is it usually pretty obvious or does it need some special tests to find. Don't want to fix it and put a cracked head back on.

[Simon Jones]

I would say you have a 94% chance the head is cracked, a 4% chance it's just the head gasket & a 1% possibility that the main block is cracked. You could have the current head pressure tested & skimmed which might cost £100 & once re-assembled you may find the problem still exists. Alternatively, bite the bullet & get a good quality (not Chinese) head & have it properly installed. Do some reading on here regarding 'decking the block' to ensure you have a good fit between the new flat head and the existing block.

As NB says, it is well worth identifying if there is another problem that may have lead to the problem such as a split hose, rusty coolant pipe or leaky water pump.

[rita]

You could also try......
Steel Seal

Revolution in a bottle! This stuff will get you out of trouble if you develop a cracked cylinder head.

[scanner]

You could also try......
Steel Seal

Revolution in a bottle! This stuff will get you out of trouble if you develop a cracked cylinder head.

Not "will" - MAY!

Will = 100%

May = 0% or more.

[Simon Jones]

It may fix head gasket issues but wont fix significant cracks in the head or block. Is it worth a go? Probably, if you're on a tight budget and can't justify £500 + to get the work done, then there's very little to loose as they offer a money back warranty. Bear in mind it is only as repair so will never be as good as replacement.

You may struggle using it as per the FAQs http://www.steelseal.co.uk/how-to-use-faqs as you wont easily be able to disconnect two cylinders & make it run long enough to get up to required temperature:
Additional Steel Seal Directions:

These directions are for people that have a lot of back pressure building up in the cooling system, usually shown as bubbling in the header tank or air forcing past the coolant cap.
•Locate the cylinder causing the bubbling in the overflow tank or backpressure. (Remove plugs one at a time till bubbling stops)
•Before starting the engine, remove the spark plug or injector from the cylinder that was causing the bubbling in the overflow tank or back pressure. If accessible, remove injector wire from that cylinder. This will limit the amount of unburned fuel going into the combustion chamber.
•If you cannot find the spark plug that is missing, run the engine with the coolant level down to the top of the radiator core and with the radiator cap off or leave the expansion cap off the expansion bottle with water only just visible.
•Make sure to run the engine up to temperature with the spark plug/Injector out and for the one final time with the spark plug/injector back in place.

[widdowson2008]

You could also try......
Steel Seal

Revolution in a bottle! This stuff will get you out of trouble if you develop a cracked cylinder head.

Agree with scanner. Steel Seal aint what it's cracked up to be .
Take a look at this thread to see what Steel Seal does to your system.
http://www.igmaynard.co.uk/bongo/forum/ ... al#p512711

[Weeduggy]

Any one used this?

http://www.ebay.co.uk/itm/RANGER-BONGO- ... 1c2dcf9400

Trying to do this as financially viable as possible but don't want to scrimp on the important parts. But equally don't want to spend 150 quid if 60 quid will be just as good!

[rita]

Weeduggy , do you intend to fit a new head?. If so it might be advisable to purchase All the parts (head and gaskets bolts etc.)from the same source.

Buying These Related parts from different sources and in the event that a problem arises, it is often the case that one supplier will blame the others product.

Good Luck.

[Weeduggy]

Just planning on changing head gasket unless the head is goosed and i need to change it.

Where do you recommend, Bongo club is quite expensive.

[Simon Jones]

I hope you prove me wrong with my estimate of very slim chance of it being just the head gasket. Replace the cambelt and tensioner while you've got the head off as it should not be re-used. I think the kit you've seen on eBay will be absolutely fine.

[Weeduggy]

I hope you prove me wrong with my estimate of very slim chance of it being just the head gasket. Replace the cambelt and tensioner while you've got the head off as it should not be re-used. I think the kit you've seen on eBay will be absolutely fine.

Hope for the best and plan for the worst Simon.

Head is off so will see about getting it tested this week and source the bits to rebuild. Can you recommend somewhere to get a good quality head if the worst comes to the worst.

Will be changing water pump, thermostat, cam belt, tensioner, spring and obviously all gaskets as a matter of course.

I've looked around the internet and plenty of places do heads,some bare, some built, but no idea of quality.

Any help would be appreciated with regards to spare parts and getting it rebuilt and back on the road.