Overheating, how do you remove air pockets from the cooling system

TRAMAYNE

MEMBER
1997 ROVER RANGE ROVER
V8
4WD
AUTOMATIC
140,000 MILES

The car started to run hot yesterday and I pulled over and took the upper radiator hose off and air blew out along with coolant. Left it off for a few minutes then pour more coolant into the block and car ran just fine. This same thing happened a week prior. I went ahead and changed the thermostat but wanted to know how to remove air pockets. The radiator and water pump are less than a year old. The engine was replaced a year ago as well.

7 Replies

DAVE H

MECHANIC
13,383 POSTS

If you did the same thing a week prior, the coolant is going somewhere, it cannot just evaporate from a closed cooling system. Inspect around/below the water pump and radiator for signs of a leak or dried white crust that would indicate a leak that is drying instead of making it to the ground. If no leaks can be found, you may want to chemical test it for a blown head gasket, not unheard of for these vehicles.
Here are a few guides on leaks, how to find them:

https://www.2carpros.com/articles/coolant-leak-symptoms

https://www.2carpros.com/articles/radiator-pressure-test

https://www.2carpros.com/articles/coolantantifreeze-in-the-engine-oil

Check these out and report back with what you find.

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Sunday, May 3rd, 2009 AT 5:28 AM

GLEN ALLEN

MEMBER
1 POST
1998 ROVER RANGE ROVER
V8
4WD
AUTOMATIC
126,000 MILES

I have replaced, with new parts, the thermostat and the radiator this month. Overheating still persists although less severely. What am I missing?

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Monday, September 24th, 2018 AT 5:59 PM (Merged)

DAVE H

MECHANIC
13,383 POSTS

Flush the cooling system and check cylinder compression.

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Monday, September 24th, 2018 AT 5:59 PM (Merged)

AIRBUSPILOT

MEMBER
1 POST
ROVER RANGE ROVER

Range Rover 4.0 V8 123,000 miles.

I had overheating problems before so I changed the coolant, radiator and thermostat.

Although a bit better, the problem persists.

When in a traffic jam, with A/C running, the engine temperature slowly creeps up towards the red zone. At a certain moment the overheat problem kicks in, shutting off the A/C compressor, which stabilizes the problem. Highway driving is no problem at all, only when idling with A/C on

As soon as you start driving again, the temperature goes back to normal.

The system pressurizes well and the coolant level is stable.

Could it be a water pump problem?

Thanks

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Monday, September 24th, 2018 AT 5:59 PM (Merged)

2CARPRO JACK

MECHANIC
11,533 POSTS

Mechanical fan? If so try a fan clutch.

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Monday, September 24th, 2018 AT 5:59 PM (Merged)

DON CHIP

MEMBER
2 POSTS
1998 ROVER RANGE ROVER
V8
4WD
AUTOMATIC
103,000 MILES

Car overheats if driven for two to three miles but does not overheat parked and idling.
Thermostat looks to be okay. I flushed the system as well but problem persists.
I suspect water pump but do not know how to check if it is pumping.
If it is the pump I cannot get to all the bolts with the fan attached to the shaft. Can you please detail pump removal steps? Including how to get fan with clutch off the car.
Thanks

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Monday, September 24th, 2018 AT 5:59 PM (Merged)

RASMATAZ

MECHANIC
75,992 POSTS

You do not look at the thermostat and declare it it is good. You have to test it or replace it. Cheap fix for the water pump see below:

One way to test for a bad water pump is to squeeze the upper radiator hose when the engine is hot and idling. Careful, because the hose will be hot! If you do not feel much coolant circulating through the hose when you rev the engine, the pump may be bad. The other cause might be a bad thermostat that is not opening properly (remove and inspect the thermostat), or a clogged radiator.

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Monday, September 24th, 2018 AT 5:59 PM (Merged)