P38 Overheating... Radiator?
 

Hi guys,

I just recently replaced the head gaskets on my 1998 Range Rover. I thought I had everything finished up, but when I took it down the road, it overheated. the water pump was leaking from the weep hole. So I order a new water pump and installed. After replacing the water pump, it was still overheating. So I order a new thermostat and replace that. No change at all. It seems to build pressure very fast on the upper radiator hose. I'm thinking it maybe the radiator is clogged up? I have been filling the system with water only for now until I get everything working properly.

If I start the engine cold and take the cap off the overflow tank water will splash out violently.

Any help would be greatly appreciated.

Oh one more side note, the rover has been sitting for seven years, before I fixed the head gaskets. No water in the oil though.


Thanks, Jason

possible blockage in the radiator , alot of air in the system or bad head gasket job combustion into the cooling system do a test

Brass radiators (older Rovers and Discos) are a side tube (horizontal) design, so gunk settles to the bottom and clogs row after row of tubes. If a previous owner used "stopz leekz" a tiny portion of the material stopped the leak for a short time, the rest of the bottle pretty much settled to the bottom of the radiator. About $65 for rod out at indy shops in my area, try to find ones that work on tractors and big equipment, they are cheaper on baby radiators. Newer aluminum radiators usually have plastic side tanks, may be flushed, but some shops won't rod them out.

Restricted radiators will usually not feel (or read with IR thermometer) the same temp across their fins.

Of course, stat must be inserted correctly, spring inside block. And the combustion gas test you can buy at auto parts store, good idea before you re-do the HG.

Based on the "very fast" and "splash" comment, I would guess HG problem, hard for radiator to do that so quickly unless blockage is severe. Guess a home brew test could be to detach upper and lower hose from radiator, feed lower hose with water from a garden hose (like testing an outboard boat motor), and observe what comes out of the upper hose - spits and spurts and steam might point to the HG or worse. You are also then set to do a flush of the radiator.

i just got finished overcoming this issue with my '97 4.0. turned out to be a bad sleeve in the block, ended up replacing the whole motor since it was cheaper...

hopefully your problems aren't that serious but mine were!

Thanks guys for the advice. If combustion is leaking into the cooling system, should I be able to see it by checking the compression?

Maybe, maybe not so easy. The chemical combustion gas in coolant test kit is like $50 at the auto parts store. With compression test you might miss something, or the leak may be so small that the PSI difference is slight. Think thermostat might be in backwards? Slid down on gasket when installing? RTV gooped on thermostat? Cheap to inspect.

You can also do a chemical flush of the radiator, may help some.

If you have access to a scanner that can read live data your year Rover should provide that (coolant temp) which can tell you more than the dash guage will.

from your info a block test should be performed a 50.00 tester from NAPA WORKS WELL
Once this is done you probably find that the block had a bad sleeve or said another way its toast,

NOTE if you just put on new HGs and I would assume you had a valve job done then the block is usually the failure point

Also do a coolant pressure test to make sure you have no more leaks, internal. You should test the system for at least 15 minutes at 18 pounds. In the mean time, quir driving it or you will be looking for a replacement engine.

do the home brew test like savannah said. If its clogged, you just saved yourself some coin on its replacement as opposed to performed the test that actually cost $$. Always check the stuff you dont have to pay for first. If it flows, then your SOL.

You can pressure test your self with loaner / rental tool sets from the national chain auto parts places. So it is practically free.