How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask DBranch Your Own Question
DBranch, ASE Certified Technician
Category: Car
Satisfied Customers: 706
Experience:  Factory trained Silver Certified Land Rover Technician. 7 years of automotive experience.
Type Your Car Question Here...
DBranch is online now
A new question is answered every 9 seconds

It started overheating so I replaced the Fan Clutch..flushed..radiator

Customer Question

I have a 96' Land Rover Discovery with a 4.0 engine. It started overheating so I replaced the Fan Clutch, thermostat and cleaned and flushed out the radiator. It goes 35-45 minutes with no issues then it starts overheating again. The temperature goes up then it will come back down to normal then back up again after a couple of minutes. Idles fine with aircondition on no problem. It happens after a period of driving.

What could cause this?
Submitted: 6 years ago.
Category: Car
Expert:  DBranch replied 6 years ago.

Welcome to JA.


First make sure there is no air in the system it can cause the temp guage to fluctuate remove the plug on the top of the radiator and pour coolant in it and in the resvoir until both are full. Then you need to have a pressure test done to check for leaks in the coolant system. But from what you are saying it sounds like a clogged radiator. So what you need to do to check for this is to get an infared thermometer and bring the car up to operating temp. Check the temp on the radiator from top to bottom. It should be hotter on the bottom and progressively cooler towards the top radiator hose. If you find any spots that are excessively hot compared to the rest of it that is your clogg. Given the age this is most likely the problem. This is where I would start. Thanks Daniel

Edited by DBranch on 11/2/2010 at 1:33 AM EST
Customer: replied 6 years ago.
The radiator was clogged and the radiator was unclogged by radiator shop. The coolant resovoir was filled half way to the fill line and when it overheats the pressure seeps through the resovoir cap. Pressure test done to radiator last week when it was cleaned.
Expert:  DBranch replied 6 years ago.

Ok good. The whole cooling system needs to be pressure tested with radiator in the vehilce if this was not done. This way you know that there are no other leaks. Make sure there are no blockages in front of the radiator. leaves etc. and that the belt driven fan is working properly. The electric fan comes on with the ac so that pulls more air and cools it better. If you cut the car off after it has been running and hot turn the fan it should have drag and only turn about 1 time. Also if the fan shroud is broken or missing the top piece over the fan it will not channel the air right and will cause it to heat up. Let me know. Thanks

Customer: replied 6 years ago.

The belt driven fan has the fan clutch and it seems to not throw that much air. The shroud is in great condition and channels the air fine.


How much play or how hard or soft should the fan clutch be? If the fan clutch was bad would it be doing what it is doing(temperature fluctuate)?


How can I ensure to fully remove the air from the colant system?

Expert:  DBranch replied 6 years ago.
If you are having fan issues then it would heat up more at idle and not while driving down the road or highway. It should have drag on it with the car hot when you try to turn it which means that it is engaged it should spin no more than a 1 or 2 turns when you try to spin it.
Customer: replied 6 years ago.

Daniel how do I know I have the air out of the coolant system? What do I look for?


When you say fill the resovoir coolant tank is that to the fill level or top it off?



Expert:  DBranch replied 6 years ago.

Sorry I didnt answer that part. There is a 21mm plug on the top passenger side of the radiator. Take it out and fill up the radiator until it is to the top. This will partially fill the resvoir up. Then fill the resvoir up about 3/4 and you should be good. When you put the plug back in dont tighten it too tight or it will break.

Edited by DBranch on 11/2/2010 at 2:23 AM EST
Customer: replied 6 years ago.
Based on what I have told you Daniel is the air in the coolant system the likely cause?
Expert:  DBranch replied 6 years ago.
It could cause the guage to fluctuate due to inaccurate coolant temp readings. It could be an issue but air in the system is usually caused from a leak. I would definitely check this since it would be easy.
Customer: replied 6 years ago.

I will try checking the air in the system and have the system pressure tested. Can the radiator guy check with pressure for the leaks in the coolant system?


How do I do it to ask for you tomorrow if this still doesn't work? What other cause is possible if this does not work? Believe me I want this to be the issue!!!!




Expert:  DBranch replied 6 years ago.
Either log back into your account or a link in an email sent to you when I responded. Not sure if he can check just ask if they have the ability to pressure test it. Check those things and let me know. Then we can check for other blockages etc.
Customer: replied 6 years ago.

Land Rover has only one electric fan working!!! Would that be the problem???

Expert:  DBranch replied 6 years ago.
Sorry I didnt get back with you sooner. Yes that could be a problem and needs to be rectified and the system retested. Most likely it is a bad fan but you can hook power up to it and see if it operates. If it doesnt replace it. Thanks

Edited by DBranch on 11/5/2010 at 11:36 AM EST
Customer: replied 6 years ago.
The rover did have a bad fan I replaced it and now the temp is normal but, when I got back from ranch after a 1 hour trip at 65-70 MPH when I got home water started coming out of the Coolant tank and temp was normal.....What could have caused this or what is causing this?