Any engine gurus out there ?

Dr. Dre

The other day, I found my car to be overheating and discovered to my dismay that there was no water left in the radiatior.
I subsequently refilled it and, today the heating doesn't appear to be working, the auto-choke is also staying on longer than usual and is rev'ing at about 2000rpm whereas before it used to rev at 1700rpm.
what's going on ?
and is my engine now f*cked ?

PS: the temp gauge is indicating normal.

Cheers

mike65

You mention heating not working today, do you mean no warm air in the car? If so thats proberly your heater matrix shot. Or a pipe has come adrift.

Mike.

Dr. Dre

yup, no warm air in car.
hmm, I must check all the pipe fittings.

mike65

Have a good look under neath the dashboard area, you may discover some coolant on the carpet or slowly dripping from somewhere, then look inside the engine bay under the engine and see whats freshly damp.

Mike.

BrianD3

The non working heater may be due to an airlock in the system. This can happen if the coolant drains out and you refill it without bleeding the air from the system.

Has the car lost any more coolant since you refilled it? No coolant in the system will obviously result in a non working (cold) heater.

As for the change in revs - a blown head gasket can cause poor running and other problems. This could also explain the loss of coolant. And unfortunately, if it wasn't blown before it could be blown now (letting an engine overheat can cause it to blow)

You'll need to provide more info really. Probably best to take it to a garage. PS I hope you didn't put cold water into the car directly after it overheated.

good luck!

Brian

Dr. Dre

Originally posted by BrianD3
PS I hope you didn't put cold water into the car directly after it overheated.

Yup, that's exactly what I did.

I was thinking along the lines of the head gasket, that's mad expensive isn't it ?

And how do I bleed the air from the coolant system, will I just leave the cap off the radiator overnight ?

mike65

Adding cold water may have cracked the rad!

Bleeding the system therefore may be a waste of time.

I'd take it in to a garage pronto tomorrow morning.

Mike.

BrianD3

Re: bleeding the system - On my car there's a bleed screw on the top rad hose. When filling the system, you leave the screw open and the air is forced out, once coolant starts coming out you close the screw. I don't know what you'd do since you've already filled your system. Might be a good idea to drain it completely and fill it again with the correct antifreeze/water mix.

You could try this first anyway, if you're lucky it might be something simple like an airlock. It is possible that you did some damage to the rad or even the engine block by filling a hot engine with cold water or that your head gasket is gone. Of these, the head gasket is probably the most likely. Cost of replacement will depend on the type of engine really. On an older, simple engine eg an old ford it would be an ok job. On a newer more complex engine it could be very expensive.

Best advice is to take it to a garage and let them have a look.

Brian

ozpass

Replacing a head gasket is a tedious job (you can do it yourself with a decent socket set and a torque wrench) but what caused it to blow is the issue. If your engine has an alloy head, chances are the head itself will have warped. I've built many, many racing Hillman Imps (all alloy motor in the Imp) and I've lost count of the number of times I've seen this. If this is the case you'll need to get the head milled flat again. This will cost you more than scrap engine though.

What car/age?

mike65

Dr, did you get it sorted? Is Christmas cancelled?

Mike.

Dr. Dre

Yup it's sorted ! Xmas can go ahead as planned !!

Turned out that there was a leak in one of the pipes that carries the coolant around the engine, so a jubilee clip and a spot of radweld later, it seems to be OK.

Thank you all for your advice.

Gav.