I bought a 97 HSE range rover with overheat problem. No water in oil , no detectable combustion gasses incooling system. Thermostat had been removed by previous looker. Can no thermostat cause engine to run hot/boil? Ive looked at the usual ,water pump ,radiator hoses, radiator etc and on seeing other threads wonder why the Range rover overheat is so hard to detect.?

 

Have you tried verifying that its over heating? The gauge lies sometimes. Use an OBD scanner that can read the engine temps from the computer, or use an infrared temp scanner.

 

Yes, Ive had it to 2 mechanical shops and its still undiagnosed. I did have a couple of days normal traffic driving for no overheat, then I had air conditioning on and a very hot day for temperature to climb and subsequent boiling. It runs smoothly no knocks and 2 mechanics looking for head gasket problems but not finding one, i would love to keep it. Are problems always this hard to isolate. I just see the same problem over and over from others when describing Range Rovers. Is it possible that many overheating and consequent head ,liner, and pressurising problems are caused initially by intermittent radiator blockage. In which case radiator servicing or replacement every 2 years or so might work out cheaper solution.

 

Running with no stat won't usually cause overheat in moderate climates. I ran without one in my D1 and the temp came up to about 145 - 150F on my scanner, 90F outside. A vehicle without a stat is usually a sign of previous owner fight with cooling issues. The lower temp decreases the effectiveness of the oil, and decreases mpg.

I would check the following:

Rad obstructed - when warmed up from running, fins (not side tanks) will read cooler on bottom rows if full of gunk. Like more than 10F difference top to bottom. And you have in effect half the radiator you need. If this is the copper brass radiator it can be rodded out and hot flushed by an indy shop for under $100, you carry in. New rads are very expensive (like $600), and there have been some aftermarket aluminum ones recently available for $230ish.

Thermostat - I would install a 180F one.

Serpantine belt - be sure route is correct - compare to tech manual

Electric fans - be sure when they come on that a paper towel is held against grille rather than blown away. I had a PO that installed replacement fans and wired them to run backwards, which subtracted air flow when they were on with AC.

Main fan - cupped side of blades goes toward block

Fan clutch - spin in morning when engine cold and release - will feel like peanut butter inside, turn maybe a quarter turn when released. Warm up truck and repeat with engine off. Should turn a little more when released, but not a whole revolution.

With AC on you need extra cooling when going slow or stopped, so the electric fans should be coming on. But Murphy's Law says it can be more than one thing. In my case, it was bad fan clutch, belt route incorrect, almost dead water pump, encrusted radiator, electric fans wired backwards, and a pile of leaves and scum between main radiator and AC condenser. The point I'm trying to make is that the extra horsepower load of the AC is not the issue, it is all the other little things that can go with it.

Also, don't trust the heat gauge above 50%. If you connect a scanner or Ultra Gauge to the diagnostic port, you'll see temps in real time digitally. This helps you avoid getting too hot while you work thru this. Rover heat gauges are not known for being precise instruments. With my D1, 180F stat, 95F outside, 55 mph I'll make like 180 - 183F. Pix of what temp gauge can show and what scanner shows, on a D1. Don't expect RR to be any more precise.

I would think that head gasket or cracked block problem would not care if you had AC on or not, so I hope you just have a simpler problem.

 

Many thanks. Plenty to investigate there. Ill let you know how I go. I just finished reading an article by Chris Crane Of RPI engineering and his description of a cracked block sounds horribly like my problems. Ill check everything else out first. Harry

 

?how about a leaking heater core orings?

 

And those qualify for the hard to find for sure!

 

If the block is cracked are the tophat liners the answer or is it curtains for that block.

 

I don't think top hat liners are the fix for a cracked block.

 

Seem to have isolated it now. Radiator was 60% blocked. Have run for 2 days with no problem . A discharge from expansion tank this morning after 5 km and turned off caused angst but turned out to be just overfull. Towed a loaded trailer for 90 km in and through traffic, no sign of overheat. Let it cool right down and just went out to move in the early evening and noticed a reasonable amount of condensation. Ive checked other threads that indicate this is ok. What do you think. Maybe that block or liner showing its colours or is this standard. Ive got to tow 350km tomorrow so that should settle it one way or another.