Need help ASAP: Coolant loss

[shore_rider]

Hi my name is adam, and I recently bought a 93 sport. Upon buying it I noticed it had a coolant leak. So I have searched a few forums looking for common places (intake, thermostat, hoses....) and still havent been able to find anything. Although on cold starts for the first 3-4 seconds I can hear a loud scrathing coming from the water pump area which I am guessing means the pump is pooched and needs replacement (bearing). Another thing is that the water temp gauge in the cab seems to take forever to 'warm up', and if I turn on the heater the guage jumps up a fair bit.

So from looking, everything is getting hot, rad hoses, rad itself heater core hoses and so on. From looking at the oil when changing it and the dipstick nothing is leaking into the oil, and no white smoke on start up that i can tell.

So thank you for reading this, any kind of opinions, experience or help would be greatly appreciated.

 

[MrShorty]

I don't know that there are any places for coolant leaks that are "automatic" diagnoses. Best first place to start would be to get a pressure tester (in the states, places like autozone will borrow them out when you pay a deposit) and pressure the cooling system up and see if the leak is external. Most of the time you can find an external leak this way.

 

[Canadian Rob]

Can you physically see the fluid coming out? I had a similar problem with my ex when I first bought it, and it turned out that the water pump was fouled, and that fluid was leaking from the weep hole. Just a suggestion.

Oh, and before I changed engines, I also had that loud 'scratching' sound coming from the water pump/engine compartment, and it turned out, my engine wasnt getting coolant at all... If there isnt heat coming out from the vents, and the hoses get hot, there isnt coolant, well, from what's happened before to me anyways..

 

[manaen]

If you cannot get a pressure tester you could also heat up the engine and carefully look around for drips/leaks in all the coolant hoses, water pump. if you don't see anything you may want to pull all the plugs and note any plugs that look like they are burning coolant (could be a head gasket).

 

[shore_rider]

Ya the coolant seems to be circulating, the heater core is blowing hot air, and i think i can feel a surge when reving and holding the top rad hose. As far as the pressure tester I think I may be able to grab one from work tomorrow to test it (going to cross my fingers that it's something stupid). thanks for the quick replies

 

[shore_rider]

Ok so today I got the coolant system pressure tested and was told that I either have a leaking intake mannifold, blown headgasket, or a cracked head. Although he could not tell which one. So now my question is how to find out which? So far the engine does not run like garbage (as I am told it would if the head or headgasket were gone). Thanks

 

[MrShorty]

Does that mean he couldn't find an external leak, so he's decided it's internal?

Any feel for how much coolant you are losing (1 quart/week or what)?

Intake manifolds have been known to be problematic on the 1st gen 4.0 OHV. Does the engine ping under load? You might try tightening up the lower intake manifold bolts to see if that fixes it.

 

[shore_rider]

Well they couldn't find an external leak, so they pressure tested the system by attaching a pressure gauge to the rad and starting the truck. he showed me the guage and on idle the pressure slowly rose, but when reving it rose substantially. So he said it is definately leaking into the engine and said it could be either of the 3. It seems to be losing maybe a litre every couple of days or so. I will see if tightening it helps at all. thanks

 

[MrShorty]

I just did my intake manifold; I'm not sure if I could see pressure getting into the cooling system from a bad intake. It would appear to me you have a head gasket/cracked head.

Do any of the spark plugs show sign of contamination? Have you tried (or did you mechanic try) a compression/bleed down test? If pressure is getting from the cylinders to the cooling system, it would seem that a compression test with one of those adaptors and compressed air would help to determine which cylinders are contributing to the problem and which aren't which might help determine what the problem is.

 

[manaen]

if you don't see anything you may want to pull all the plugs and note any plugs that look like they are burning coolant (could be a head gasket).

pull the plugs x2

they will tell you which cylinder is the problem, and then you can start to tear it down from the top down when you start taking off parts then you will find the leak. If the plugs look OK then head/intake gaskets are not your problem.