EnyChevyUK

Hi, my 1998 5.7 Express van has developed a coolant leak. It is leaking from what looks like a big nut on the drivers side of the rad under the top hose. It is probably some sort of blanking plug for an additional coolant hose ?
Can anybody tell me the correct name for this plug so I can try to locate a new one (that is if they are available ?).
Thankyou.

MDTAHOE

That is where the oil cooler or the trans cooler connect. The only repair is to replace the radiator.

EnyChevyUK

Thanks, I think I'll leave it for now or try some sort of sealer, can't believe a new rad is required.

saabman

Hi Did you get any further with your leak?
Mine is leaking... And I can't figure out where...
Fearing the dreaded intake manifold gasket...

therewolf

If it's a Vortec V8, saabman, it's more than likely the waterpump mounting gaskets...

saabman

Hi well I am not sure... it is a Vortec V8 but the water seems to be coming from above the water pump where the lower intake manifold joins the block...

I was wondering if a pressure test would show the leak - should do? If so how could I pressure test the cooling system?

MDTAHOE

You need intake gaskets.

saabman

Yup think so...
Leaking front and back

EnyChevyUK

Well, I decided when carrying out a service to drain the rad, flush and replace with new coolant. This was an ideal time to go around the whole system checking and tightening anything I could see. I removed all the hoses to check for splits etc and replaced all the 'jubilee clips' (thats what we call them in England).
I also removed the small black clips which hold the overflow hose in place and the hose from the expansion tank to the top of the rad next to the cap.
I replaced the rad cap.
I also managed to tighten up the 2 hexagonal blanks (top and bottom), they were not loose but did turn.
I no longer have a leak from the rad. I was quite surprised when going around the system to find most of the jubilee clips were not as tight as they should have been so it is worth while checking everything whenever you have the opportunity rather than when you have a problem as it could save you a lot of money/time.
The only problem I have now is coolant is leaking from what I think is the water pump, it looks to be coming from the area behind the bottom pully (is this the location of the water pump ?).
Thanks.

saabman

Hi Thanks for that info!

I am British too so Jubilee clips is fine by me
I checked my pipework and all is fine, also pressure tested the system and found no obvious leak...

I have my leak in the same place as you mention...
I would say could be water pump or intake gasket... or both...

I am going to test drive a bit and see what happens now... But I fear I will have to go to a shop and get the intake done...

On that topic I heard that the Fel-Pro gaskets are the best for the job, is this correct?