Overheated and coolant spewed out of header tank

[samuel]

Overheating - I have feared this for ages and it has now happened (i think). Oddly enough the same thing happened last year but the day before we left for the Bongo Bash. Our Bongo spewed its coolant out of the header tank. I topped it up and all was okay until now! Last year i put it down to putting the header tank cap on the other way i.e. 180 degrees out. I put it back to its normal position and all was fine.

I'm hoping, perhaps on a wing and prayer, that if i actually put a new header tank cap on the problem will disappear again!! I'll also check the surface of the header tank where the rubber seal sits to make sure it is free from scratches.

Popping down to Halfrauds tomorrrow morning to hopefully get a replacement cap.

At this point in time the sump oil has not become contaminated, the coolant doesn't appear to be discoloured and i don't get bubbles in the header tank when i start the engine from cold and allow her to warm up.

With the Bongo bash only a week and a half away it is a bit of a worry. I'll let you know how i get on later tomorrow.

[mikeonb4c]

Fingers and toes crossed for you samuel. Out of interest, what were the circumstances. Had the engine block had any reason to get hot (lots of standing in traffic, working in hilly country, hot weather etc.)?

[missfixit70]

Hope it's that simple Tim Can't remember if you've got a coolant alarm or Mason? If not, I'd definitely recommend it if you're fearing the worst is going to happen, great peace of mind. Certainly had my Mason alarm chirruping going up some of the mountains fully loaded over the last couple of weeks.

[samuel]

Good morning Mike and Kirsty and thanks for your supporting comments.

I've had a small leak on the rear heater hosefor quite some time, the one that comes off the blockon the drivers side and just keep toppinbg up with small quantities of water now and then.

Yesterday we drove out about 8 miles. Heard this hissing sound and put it down as a stone chip in the wheel caliper. We'd just come off a loose stone area. Thats what it sounded like! On the way home the temperature gauge started rising. Got home, let her cool down and topped up with about 8 pints!!!

As stated i had a problem with the cap before. I tried it and it does appear to not give much pressure when i screw it on. Off out shortly to get a replacement and go from there.

Talk later.

[mikeonb4c]

There's been a discussion here before about whether a pinhole crack could pull in air when the system cools hasn't there? I'm trying to remember the theory - I think it is that as the system warms and coolant and air above it in the header tank expand, it pushes coolant out of the pinhole. As it cools and contracts, it pulls air into hte system via the pinhole. The air may move away from the area of the pinhole, rising to the highest point it can. This all gets repeated on every heating/cooling cycle, slowly causing more air to get in the system. As more air gets in the system, the 'ejector pump' gets more potent as air expands more than coolant and there's more an more in it. This creates a more explosive pressure and may exceed the limit of the header tank cap. Also of course, more air gathers in favourite spots in the system, risking hotspots, disrupting flow (cavitation in water pump) and in any case it reduces the volume of coolant and thus the cooling capacity. Eventually, you get an event.

This could all be balderdash but I think it hangs together as a theory. If so, bleeding the system ought to chuck out the air for now. Then either replace that hose or at least get some hose repair tape to put round the offending section for now. And, as Kirsty says, put the Bongo on 'special measures' by fitting a Mason alarm (or TM2) so you can be alerted to any deterioration in engine temp performance.

Good luck - keep us posted

[samuel]

Thanks Mike

Your comments are very useful and there is a chance this might be my problem.

Halfrauds didn't have the right cap when i checked today so will try the local Ford garage tomorrow. Hoping a Ranger one is the same type!

I ordered a silicone hose from Mike Smart on Saturday.

Will have another go tomorrow.

Cheers

Tim

[francophile1947]

Moved here, as help more likely on this section

[haydn callow]

It makes no differance which way round you put the expansion tank cap on.
If you have been driving around with a known leak, and topping up as required you have really been pushing your luck.
If you lost 8 pints of coolant I can only assume you do not have a low coolant alarm fitted.
Losing 8 pints will have let air into the system and just topping up will not get rid of it.
You MUST bleed the system properly.
You say the gauge started to go up !! not a good sign...lets hope no damage has been done.
Get the hose replaced...bleed the system according to the instructions.....hope for the best outcome.

[bongomaan]

hi samuel the header cap is the same as a shogun part no QH c64 available in any motor factors for £5, but make sure its the yellow one cos the red one is for the radiator...good luck..neil edit...of course i wouldnt be without mason or haydn alarms money well spent...

[Doone]

Tim you have a private message.

[stilldesperate]

Halfrauds didn't have the right cap when i checked today so will try the local Ford garage tomorrow. Hoping a Ranger one is the same type!


Cheers

Tim

Hi Samuel,

I should have a spare cap somewhere, if you PM me no later than mon eve, I can have a look for it Tuesday.

SD

[the janner vanner]

Sorry to hear you are having a problem Tim, lets hope you'll have it fixed by next Wednesday. With all the info flying your way I should think you'll have the problem solved very soon.
Keep us posted,
Dave

[samuel]

Lorna

Thank you for your pm. have replied to it.



Hi Dave

Thanks for your support. I am presently bleeding the systemof air and have manged to find a new header cap. There is quite a bit a difference in the spring pressure, the new one being a lot stiffer, so i am hoping the old one was past it. They are both rated the same so this might be the answer.

Will let everybody know later on how it is going.

[samuel]

Bongomaan Thank you for the part no. One slight problem. When i went to get that one we found it was only rated at 0.5 bar. It says 1.1 bar on the original.

Stilldesperate Thanks for the offer. have managed to get hold of a blueprint one locally.

Am presently bleeding the system and will update this later.


Cheers

Tim

[haydn callow]

0.9 bar is best for the header tank....it really needs to be less than the one on the radiator....
I doubt the new cap will cure the problem.....it may mask the problem (whatever it is)
for a while. But hope for the best and keep a very sharp eye/ear on things.
Good luck.