The guy thinks its the waterpump but he says it takes awhile for it to overheat while idling and that it takes about 30mins of driving before it overheats. It has 158,000kms on it, not miles so it's not too high. I can get it for next to nothing. He says that the oil and coolant are not contaminated so possibly not a headgasket. He says it still runs nice and quiet so the sleeves haven't dropped Basically I just want to know what specific things I should look for and also what the knowledgable people here think it is. Is it the waterpump, thermostat, rad or headgasket?

Any info tonight would be great as I am looking at it tomorrow.

Thanks

 

Being I am the off-duty village idiot, I will point you at a few things.

1. He could be mis-stating the facts, and things could be worse. Define "overheat" on the guage - the normal position for a healthy truck is 8:00 - 9:00. See pix of guage and scanner data. He could have dumped in two bottles of "stopz-da-leekz", and has momentarily stopped the elak, but also clogged up the radiator.

2. Things to check and why:

A. Radiator could need to be replaced or rodded out. This will make things overheat more at slow speed but also at freeway speed. If usable, an indy shop can do this for $50-$75, but it might be beyond help, several hundred for a new one. If radiator is clogged it may show hot and cold spots across the surface. A DIY flush won't help much. There is a space between radiator and condenser that can get filled with trash.

If you buy this truck and need to drive it home, you can add some "water wetter" to the existing coolant. That will help some. Do not drive when hot, or higher end of scale on guage.

B. Water pump is a suspect, especially if it wobbles on the pulley while idling - about 1 hour to replace, easy DIY. Thermostat is $10 -$15. See pix of water pump, this one wobbled the pulley and started eating aluminum.

C. Head gaskets show up as: oil in coolant, coolant in oil, external leaks down back of engine, white smoke out tail pipe. HG can put combustion gas bubbles into the coolant system, this shows up as a "gushing" sound under the dashboard. There is a $50 test for this you can buy at auto parts store. DIY head gaskets is $300 parts, $200 machine shop if needed, two weekends.

D. Fan clutch may be suspect if overheating at idle. Spin fan when cold, should be stiff, not go very far. Spin again when fully warmed up, should go farther, but not freewheel a whole revolution or more. $49 Chevy substitute fan clutch. Makes no difference on the freeway, just when stopped or slow.

E. When AC is on, the electric fans in front should kick on.

F. Belt route - see: Discover Defender Maintenance Tips, Accessories, Parts & More at Roverparts.com

G: Other things to look for: https://landroverforums.com/forum/di...scovery-21328/

 

Savannah, excellent post. Just thought I'd but-in and tell you.

 

I have more time since work is slow. I don't know how I can keep up with those shade tree guys in northern California - their warranty is four times what mine is - I don't know how they stay in business....

 

Savannah, when you say the thing about the gauge I get nervous. I've never had either the D1 or D2 below 9/3 after it's been running a bit. I do have problems on both but they seem to run very well when they are in those positions. I'm definitely going to add a good temp gauge when I can.

I'm following some of your direction to test all the cooling components of both trucks. Thanks.

 

IMHO the Rover temp guage was designed to provide a wide range where regular customers would not complain. But if you look at my pix of the guage and scanner, you will see that where you want to be is the lower part to mid-part (9:00) on the guage. It is not linear. My guage reads virtually the same from 160 - 210. I have no idea what it would be on the far end of the scale, and I don't want to find out. Many new owners of high miles Rovers look at these guages and think it is just like their old Detroit iron, and it is not. 10:00 or 11:00 would be places where you want to be doing things to cool off.

Of course, you may have purchased a Rover with a marginal cooling system, and it has been running, looks normal, this is what it has always done. I would encourage owners that can obtain or borrow a scanner that can read live data to monitor coolant temp in the driveway, etc. It may be warmer than you want. The scanner will tell the tale, the guage is more idiot light than instrument. And being the off-duty village idiot, I know something about idiot lights....

On the D1 the guage is driven by one sensor, single wire, and the ECU by a two wire sensor nearby. On the D2 I believe it is still two sensors, just combined into one package with multiple wires. Have seen a post somewhere that a guy rigged a switch to bring on those fans when he was trailering on long hills. If Disco is working correctly, those fans should come on at 212, even if AC is off.

I did the following to my D1 cooling system - new fan clutch, new stat, flush, radiator rod out, and still "Frankie" (brought back to life with parts from the dead ones) would overheat at idle only with AC on - PO had reversed polarity to electric fans when he replaced them.

I would suppose if you were in an overheating situation, you could unplug the AC compressor, but turn on AC, that would bring on the extra cooling of the electric fans. Plus turn on heat, rolls down windows, enjoy nature, etc. as you limp back home.

 

Yup. Cooling flushed. Should go green maybe. Pretty new expansion tank and cap, hoses ok or replaced. Better DEX ratio used 70/30. New Amsoil oil and LR filter. New oil pump, chain, wheels. Some new engine gaskets. New-ish stat, had the radiator pulled and welded and cleaned. No rodding or acid baths.

Seems to get hot when the AC is on and I put any pressure on the truck. Has been running well but not tested hard with no AC. Checking viscous and fans this week. Engine sounds great except for belt like whirrr coming from the bit/arm that holds it. We'll take care of that this week.

Did I hijack?. If I did sorry and let me know.

 

Don't care for DEX, green is good. When you consider that people run these trucks in the desert parts of the US, and world wide, they should not overheat in suburbia. If overheats with AC on, and at say 45 mph, then radiator or water pump might be suspect. If it only does it when slow, or parked, viscous fan clutch might be suspect. Fan has no big impact at highway speed. On a D1, AC fans should be running whenever AC is on. You can verify air flow direction - hold a wimpy plastic bag near the grille, with engine off, AC set to on and interior fan running. Should pull toward grille. Of course, radiator fan blades should be cupped side toward engine block.

Most of the variables are "in" the radiator - as it gets more gunk inside, it cools off less. Outdoor temp goes up, and eventually you get to a point where it can't keep up as a system. A cold spot in the radiator or a air blockage (trash or mud in fins or between rad and condensner) blocks air flow to fan clutch. If front of clutch stays below 170F, it does not come back on full power, and does not cool like it should. A lot of younger techs will fix one thing, and see an improvment, and think it is cured. Might not be. And some things, like water pumps, tend to fail with other things they are attached to (like fan clutches), or shortly afterward.

But as a closed system, it is pretty simple. Easier to troubleshoot that alarm immobilzation or Death Wobble.

 

Stay away from it completely unless you have an extra $2000 plus in your wallet to spend for maybe head gaskets, cracked heads, cracked block or maybe just a new engine cause he dropped a sleeve after over heating it.
You are looking at a vehicle that may bury you.
Find a good one that meets your needs and have a pre-purchase inspection done by a Rover mechanic, not the dealer, that way you will know up front what sort of up-coming issues you'll need to fix.

 

But as a closed system, it is pretty simple. Easier to troubleshoot that alarm immobilzation or Death Wobble.

I'm so psyched I got through Death Wobble. I can't say enough about taking care of that when it's time. I've definitely been immobilized to the point I had to unhook the defrost and touch the contacts to get it in gear.

I really like the way she's sounding/running. I have work to do on the cooling system and will do as you suggest and let you know. Thanks again.