03' D2- I posted earlier about the AC not working because the relay/fuse was taken out by PO.

A member noted that there might be a reason he did this. Not sure if what happened after involved the AC being on, as I was not driving(but it was a cool day, so don't think they used it).

Well, not sure its related, but after this, the car overheated(250) and turns out the lower hose at the radiator blew off the radiator. Thought it might be the thermostat so exchanged with a(we think) functioning used one. Car seemed to run fine(2 trips, around 30 min each), temps up to 210 on Ultra gauge, but had these temps before we fixed the AC and had the hose problem. Well my friends wife took the car, and it started overheating. Popped the hood and the upper hose at the radiator blew off.

Consulted a LR mechanic and he thinks it is a liner that is causing high pressure in the system.

Anybody have this issue? Could it be a clogged radiator causing the pressure? Maybe bad thermostat? Or should we admit defeat and start tearing down the motor.

Thank you in advance.

Abran

 

There is $50 ish chemical test for exhaust gas in coolant you can buy at parts store, it changes color. Points at nasty things like head gasket.

Certainly if you were running 210 the radiator could be clogged up. An IR thermometer will show this, radiator will be more than 10F cooler on the bottom rows.

Steam pressure from a cracked block can do that blow off hose thing. By running a cooler stat (like a 180) you may keep the block from opening up for a while. But you could have been low on coolant, any gurgles under the dash?

You should evaluate the problem before tear down. A head gasket is a DIY project, but top hat liners and machine work can add up to about price of the truck. If radiator is resolved, and it is not a head gasket, a container of KSeal may help out for some period, as will Irontite.

 

Thanks. Had the waterfall dash problem. Noted the reservoir cap was leaking, got a new one, now having these problems.

I have the chemical test. The car is not running now(had it towed with the upper hose off). Ordered a radiator and thermostat. Will install tomorrow and run the chemical test then.

Thanks for the insight, as always you are a wealth of knowledge. We need to get this fixed properly as my friends 16 year old daughter will be driving and we don't want her to explode the motor.

 

A good bit of the D2's brought to me for overheating, are because repairs were made, but the vehicle not properly bled.

I have a vacuum bleeder for engines like the 4.0/4.6 and the RR's 4.4 M62 engines.

 

Any insight on how to bleed? We changed the radiator and thermostat today. Still have temps at 220+ with waterfall sound behind dash. Tried to burp system with the cross shaped nut on the radiator hoses at the top junction. Put a snap on pressure tester on the coolant tank, pumped it to 20 psi and it held pressure.

Also I noticed there is moisture out the tail pipe. Do you guys think it is steam from coolant boiling in the block?

I'm a total novice and feeling like this issue is out of control. I hope it nots the block, but I'm almost sure it is.

 

Normal DIY bleed is dis-mount coolant jug and elevate with bungee cord, fill while cold and let plenty of coolant and bubbles come out the bleeder T. Don't stop at first few bubbles. Re-check heat once bubble issue resolved. Air bubbles can't transfer block heat to radiator as well as water...

If bubbles continue and they are exhaust gas (chemical test) then head gaskets are indicated. Temps should not be in 220s with normal radiator fill and engine load.

I too purchased my Disco for my female offspring to drive in high school and now college. I feel safe with her driving the British "tank". I have break down towing coverage from State Farm....

 

Thanks SB. I did the bleed and still got the waterfall. I will try again. I used the chemical sniffer test on the coolant tank, no change in color. We had hoses blow off at the radiator and a master mechanic at rover said possible liner issue causing to much pressure, so I'm expecting the worst but hoping for the best.

After bleeding today temps got to 220 (idling) on the ultragauge so I got scared and didn't try to drive it.

Guess well have to try again.

 

I usually do 4 bleed / run cycles before all air is out

 

The Saga continues...

After doing a block test(Blue chemical in vile while air is sucked through) we concluded that it was not a head gasket or liner. Stumped, but relieved. Took it to a local Rover mechanic. He says he ran it for over and hour drove it around, etc and no issues. He also said temps of 220 was normal for a D2 4.6.

So, he read the codes and said that we needed a new O2 sensor. We know that but figured lets have him replace it, that was he clears the codes and we could have re-course if it was something else. Plus, Maybe the cooling problems were related?

Picked up the car, test drove for 20 minutes, got to 220 while driving. Pulled into a parking lot and the overflow coolant tank got a crack and spewed coolant everywhere!

Filled it up again, drove back to the mechanic. He changed out the tank with a used one, and then used a vacuum bleeder to pull all of the air out of the system(we were still getting the waterfall noise before this while test driving). Then used the vacuum to refill.

Drove away, still getting temps of 220-226 and still have the waterfall!

Another mechanic suggested that I take off the coolant cap, crimp one of the coolant lines going through the firewall, rev the engine to 1500, then release the crimp. He says this will purge the air bubbles out of the heater core.

Could this whole problem be as easy as air in the heater core? If so how come the vacuum bleeder didn't work? The hoses where completely collapsed when he did it.

Stumped.

 

One could just bypass heater core as a test to find out.