Range Rovers Forum banner
1 - 20 of 22 Posts

· Registered
1995-2002 Range Rover P38A
Joined
·
49 Posts
Discussion Starter · #1 ·
1996 Range Rover 4.6 HSE. I bought it new and have always maintained it myself with the exception of the factory service stuff.

So, I've gone through everything I can think of and am now considering a blood offering to the LR gods. Radiator was pulled and serviced by a guy I've known and trusted for years. New water pump. New viscous fan clutch. New thermostat. New top and bottom radiator hoses. No leaks. No blown head gasket or slipped liners. No oil in water or water in oil. No coolant loss, period. Cleaned the AC condensor. All original fan shrouds in place. The whole system cleaned and cleaned again. I'm running 50/50 distilled water and ethylene glycol and have burped and bled and burped some more. I'm using an OBDII to watch my ECT temperature in real time and the analog gauge is surprisingly accurate as well.

I even jumpered the aux fans at the R13 and R14 relays to run full time as a test and... it still overheats.

I'm about to give up and send it to the shredder. Any suggestions?
 

· Registered
1995-2002 Range Rover P38A
Joined
·
49 Posts
Discussion Starter · #2 ·
After reading through JakeIsCrazy's post I'm convinced that there is an evil deus ex machina in some P38s. I've checked return coolant flow from the radiator bleed line and it's good. I also replaced the expansion tank cap. Today I'm going to mod the old cap with a pressure gauge to see what the system pressure is doing.
 

· Registered
1995-2002 Range Rover P38A
Joined
·
49 Posts
Discussion Starter · #3 ·
I got curious about how much pressure the top of the radiator was experiencing at idle in an open system, i.e., with the expansion tank cap off. My thought was that a clean radiator wouldn't present much of a restricting force and that pressure should be very low. The system shows 7" of water column at idle. The conversion factor to psi is 0.036. 7 x 0.036 = 0.252, or about a 1/4psi. At 2500rpm I'm measuring 3psi on a precision low pressure gauge. So, either my radiator is flowing beautifully or my pump is shot, right? I don't have a functioning P38 system to compare to. It's a recent water pump so I doubt that is the problem but I'm going to pull it anyway. The old one was only replaced due to fault checking by the shotgun approach.

Tire Transport Automotive tire Automotive wheel system Gas
 

· Registered
1995-2002 Range Rover P38A
Joined
·
49 Posts
Discussion Starter · #4 ·
The water pump appears to be in good condition. The car only has 150,000 miles on it and runs beautifully. I'm almost out of options.

The viscous fan clutch is suspect. I've noticed it that when it's hot I can stop the fan far easier than I'd expect to be able to. The viscous clutch is locked up at first but disengages after a few minutes, as is expected. But it never seems to reengage when it gets into an overheat condition. But I had mechanically locked the previous clutch during testing and found that it had no impact on the overheat condition.
Auto part Automotive engine part
 

· Registered
1995-2002 Range Rover P38A
Joined
·
415 Posts
Wow. Following this thread. I'm curious to see what it is. Sorry it has been such a PITA.
Have you tried running a thermal camera or sensor over the radiator to make sure there are no blockages?
Maybe a brand new aluminum radiator would be next. At $200 it might be worth it for your sanity.
 

· Registered
1995-2002 Range Rover P38A
Joined
·
49 Posts
Discussion Starter · #6 ·
I think I found the problem. 8-0=

I just saw your post @ColoradaCrow, and we're on the same page. I figured what the hell, let's see what it looks like inside. Unreal. Moral of the story: Assume nothing, and don't loan cars to friends. And I can't wait to talk to my radiator guy on Monday.

Architecture Metal


Rodding the radiator in situ. We'll see how it goes. :)

Finger Hand Nail Electronic instrument Musical instrument
 

· Registered
1995-2002 Range Rover P38A
Joined
·
97 Posts
There's only two causes of overheating, lack of coolant or lack of circulation and you've got the latter. Before anyone leaps in and says anything about blown head gaskets and slipped liner, all they do is cause pressurisation which results in the coolant being spat out the pressure cap so you overheat due to lack of coolant. Marine engines with total loss cooling systems will run quite happily even when they are in a terrible state as they are never short of coolant.
 

· Registered
1995-2002 Range Rover P38A
Joined
·
49 Posts
Discussion Starter · #8 ·
All better now. No need for a blood sacrifice. The radiator was about 70 percent blocked. It was plugged up with some sparkly red crap and lots of what looked like cotton fibers. What the hell did he put in my car!? And the better question is... why? I almost never drive this rig so it's been sitting for a loooong time. On the bright side, the cooling system is in good shape now.

Given the amount of blockage I'm surprised at how low the radiator top pressures were. I'd have expected to see much higher pressures.
 

· Registered
1995-2002 Range Rover P38A
Joined
·
1,451 Posts
Congrats!
I would have a wee bit more than a friendly chat with your trusty radiator guy!
Curious as to what you used to release the top tank from the core? I have seen it done on a sort of press in a shop, but like Chris10, I did not know it could be done non destructively at home?
 

· Registered
1995-2002 Range Rover P38A
Joined
·
91 Posts
I'm also interested in learning about how you separated the core. I think I've got my issue nailed down, combustion gas in the coolant system. Exact cause TBD.
 

· Registered
1995-2002 Range Rover P38A
Joined
·
49 Posts
Discussion Starter · #12 ·
The plastic tanks are just held on by crimped over tabs. I just levered them up with a screwdriver with the radiator in the car. After the tedious job of rodding and flushing each tube I pulled the radiator and flushed it on the ground to make sure each tube was free-flowing, then crimped the top back on with big channel lock pliers.

My temp is stable at 195F but I ordered a new radiator just to be sure. Before I pull this old radiator I'm going to run some Cascade automatic dishwasher detergent (mmm, lemony fresh) in the system to clean out whatever gunk may be left and then rinse the hell out of it. This whole thing has been a major pain in the butt and I'll be glad when it's behind me.
 

· Registered
Joined
·
12 Posts
U may want to also get the heater core cleaned or replaced, if ur radiator was that clogged there’s a good chance the heater core is also and if that blows then u will have a seemingly endless supply of water draining inside of ur LR


Sent from my iPhone using Tapatalk
 

· Registered
1995-2002 Range Rover P38A
Joined
·
49 Posts
Discussion Starter · #16 ·
I reverse flushed the heater core until it ran clean. And after I got the system all back together I ran Cascade automatic dishwasher detergent through it for 15 minutes. I flushed the radiator by running a hose into the top and draining out of the bottom. The engine and heater core were flushed by running water back through the engine and out the expansion tank. Then I filled the whole system with water and ran it up to temp again and drained the system. An inspection probe shows that the top of the radiator core is sparkly clean.

Fingers crossed, but I think I'm golden.
 

· Registered
1995-2002 Range Rover P38A
Joined
·
49 Posts
Discussion Starter · #17 ·
Gonna give a rad with a broken nozzle a go, could be helpful with fixing a new spur into the top,, thanks
Chris, you don't have to take the radiator apart to fix the bleed nipple. Drill out the rad top and the nipple (you saved the nipple, right?) to allow a short section of stainless tube (I used a stainless piercing needle) to be inserted all the way through the nipple and into the tank. There's about 1.5" of free space inside the tank beyond the nipple. A bit of epoxy to secure and seal everything and you're good to go. I'd suggest that you insert something into the stainless tube to ensure that it doesn't fill with epoxy when you press it into the rad.
 

· Registered
1995-2002 Range Rover P38A
Joined
·
91 Posts
I reverse flushed the heater core until it ran clean. And after I got the system all back together I ran Cascade automatic dishwasher detergent through it for 15 minutes. I flushed the radiator by running a hose into the top and draining out of the bottom. The engine and heater core were flushed by running water back through the engine and out the expansion tank. Then I filled the whole system with water and ran it up to temp again and drained the system. An inspection probe shows that the top of the radiator core is sparkly clean.


Fingers crossed, but I think I'm golden.

I've heard of the dishwasher detergent but kind of though it was a urban myth haha! So did you use the liquid or the tablets? I happen to have the tablets on hand. Might give that a shot after doing the heads.
 

· Registered
1995-2002 Range Rover P38A
Joined
·
49 Posts
Discussion Starter · #19 ·
Ha! Yep, it's a non-suds detergent and safe on aluminum. I used two of the little packets of powder that are encased in the dissolving wrapper but took the powder out of the packets and put it in the top radiator hose. I see no reason why the tablets wouldn't work. If you pull the hose off the radiator, remove the expansion tank cap, and blow through the hose you can displace water out of the engine so there's no loss of detergent when you put the hose back on.
 

· Premium Member
Joined
·
1,562 Posts
Just saw the picture of the blockage, it kind of looks like gunked up Dexcool?
 
1 - 20 of 22 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top