overheating and coolant leak...help please

[papillon]

hi,

So I'm driving home and noticed the heater was'nt working very well. Looked at temp guage and noticed it had moved higher than the normal 11 o'clock position. I turned up fan on heater and stopped as soon as I could (about 3 mins later). Before I found a place to pull in, the heater had started blowing cold air. Opened bonnet and I could see that there was a lot of water that had sprayed from ( I presume ) somewhere near the top of radiator ( only happened a few moments ago so not properly inspected yet). I have re-topped up the expansion tank but only with plain water to see if the leak was obvious but nothing apparant.

I hav'nt started engine since and I was hoping to get some advice on how to proceed before I do any irreversible damage (definitely can't afford expensive garage bills). I am a complete novice at mechanics tho

Any help/advice would be greatly appreciated

thanks

[chipvan]

dont drive it anywhere and in day light bleed then inspect for leaks.
you may have caught it in time
http://www.youtube.com/watch?v=jRAKOSxgbKo

some presure test the system to find leaks or use uv dye and torch to help you.

maybe the pipe coming off the top of the rad has a crack in it(i broke mine)another story they get very brittle so look gently and dont wobble too much about!

watch all 3 vids then watch all over again before you bleed

[papillon]

hi,
thanks for reply.

This might be a stupid question but;

If the leak isn't obvious and the expansion tank is full, is it ok to start the engine to see if the leak becomes more apparant, or is that a no-no?

thanks

[chipvan]

nooooooooooooooooooooooooo

I too thought i knew better and that cost me a new head!

Bleed it up then have alook arround.

follow what they do in the 3 vids,get a helper that too has watched the vids.

I got the hang of bleeding up in the end as i did it manny many times but alas it was to late.

dont rush the steps,or maybe someone on here can help you do it?

[papillon]

ah ...ok thanks for that.
I will definitely not start it until I discover leak.

[Northern Bongolow]

get it recovered to a good garage and ask them to pressurise the system to 1 bar. do this without running the engine at all. this will show any leaks without poss damage to the engine.

or you could do it yourself . use a car foot pump or similar with a gauge on, and make an adapter that fits to the expansion tank.

[321Away]

cold air is first sign of pressure build up as the matrix is high up and the pressure builds from top down, always something to keep and eye on if you suspect your cooling system.

Julian

[papillon]

cold air is first sign of pressure build up as the matrix is high up and the pressure builds from top down, always something to keep and eye on if you suspect your cooling system.

Julian

hi Julian,

excuse my ignorance but what factors would make the pressure build up?

thanks

[Simon Jones]

Typically, head gasket failure or cracked head which allows combustion gases to enter the coolant system. Another (cheaper) possibility is a hole in one of the coolant pipes such as the bleed pipe which has allowed air to get into the system which then expands and forces the coolan out through the weakest point. The cap on the expansion tank is designed to lift at 1.1 bar to release the pressure so the coolant is forced out the overflow pipe. That's when overheating damage often occurs as there is insufficient coolant circulating to take the heat away from the head.

[papillon]

hi,

would a leaking radiator also have the same effect?

[chipvan]

yes ,would think so..have you found a leak?

[Terri & colin]

My van kept over heating and blowing cold, we gave it a good bleeding, and the was no leaks.. The next day we started the van smugly only to find it was 2 of the rubber pipes had leaks.. We did it all our selves... With help from the good bongo folk in this forum x

[chipvan]

[Klunk]

Well this sort of sums up my day.

Thought I would take my recently purchased Bongo over to Andys Imports ( Really nice bloke) over Norwich way to give it a quick look over before arranging a service. As I suspected It's seems I was sold a bit of a pup, (not from Andy). I won't go into the gory details but to cut a long story short after driving back home, a 40 mile trip, I noticed that about 10 miles from home that the heater started to blow cool air. The temp gauge seemed OK but it was definitely blowing cold. So I suspect I'm going to be rooting around in the cold tomorrow looking for leaks. Great.

[chipvan]

if not over heated then your a lucky man!! you should be happy

Looks like you have caught it before a prob cost you a bomb!