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

Tiny
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.
Thursday, April 30th, 2009 AT 9:58 AM

7 Replies

Tiny
DAVE H
  • MECHANIC
  • 13,384 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.
Was this
answer
helpful?
Yes
No
Sunday, May 3rd, 2009 AT 5:28 AM
Tiny
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?
Was this
answer
helpful?
Yes
No
Monday, September 24th, 2018 AT 5:59 PM (Merged)
Tiny
DAVE H
  • MECHANIC
  • 13,384 POSTS
Flush the cooling system and check cylinder compression.
Was this
answer
helpful?
Yes
No
Monday, September 24th, 2018 AT 5:59 PM (Merged)
Tiny
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
Was this
answer
helpful?
Yes
No
Monday, September 24th, 2018 AT 5:59 PM (Merged)
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Mechanical fan? If so try a fan clutch.
Was this
answer
helpful?
Yes
No
Monday, September 24th, 2018 AT 5:59 PM (Merged)
Tiny
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
Was this
answer
helpful?
Yes
No
Monday, September 24th, 2018 AT 5:59 PM (Merged)
Tiny
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.
Was this
answer
helpful?
Yes
No
Monday, September 24th, 2018 AT 5:59 PM (Merged)

Please login or register to post a reply.

Related Engine Overheat Content

Is Your Engine Cool Enough to Check?
VIDEO
Is Your Engine Cool Enough to Check?
Instructional repair video
Overheating Symptoms
GUIDE
Overheating Symptoms
An overheating engine is never a good thing to have happen. If the problem is caught quickly you can save the headache of a major engine repair. Knowing the information from...
VIEW MORE