Overheating Mystery

Hello again people!

I would like to consult you with something odd happened last week with my old 99 FL1 1.8 Petrol.

Firstly, if I say something wrong, stupid or ignorant please point it out so I can learn better.

-----Long Version-----
I bought my precious FL1 at 2013 and last month it overheated for the first time of 3 years. Nothing major tho, luckily I sensed something wrong and immediately I pulled over as the indicator still raising and waited for it to cool down, unplugged temp sensor and it didn't overheat so i thought faulty temp sensor is the cause.

Following days I had checked for oil sponge, swelled hose or coolant leak... Nothing! so I think HG is still ok. (I couldnt find a Hydrocarbon tester nearby)

Now the things I tried:

-Changed the sensor and it happened again while the car was moving with 100 kph and the fans were working, so now I thought it is a blocked radiator. Still overheating with a ice cold bottom radiator hose.

-Tried to clean radiators at home with compressed air blown thinking maybe radiator sheets were so dirty that air couldnt flow. It seemed to help but not overcome. Still overheating with a ice cold bottom radiator hose.

-Mechanics changed thermostat with the same brand/model he removed. Replacement thermostat is tested with hot water and working normal. Still overheating with a ice cold bottom radiator hose.

-Radiator was removed and tested with feeding water from the top hose, it easily flows from down hose. They said it is not clogged or anything. It was put back in. Still overheating with a ice cold bottom radiator hose.

-Changed the water pump, pulleys and belts. Still overheating with a ice cold bottom radiator hose.

-Heater circulation tested with feeding water from top hose, not clogged or anything. Even disabled with an U hose to test. Still overheating with a ice cold bottom radiator hose.

-Changed the radiator cap. There was a slight delay before overheating, however still overheating with a ice cold bottom radiator hose.

Then we wanted to see what happens without a thermostat and viola! No overheating at any circumstances, we tried 4 different thermostat but the problem was not the thermostat.

We gave up eventually after all these tries and thermostat replacing; and put 4 small holes at the sides of thermostat and put it in. It is not overheating at all! and bottom radiator hose gets a little warm when engine is getting warm. But it is still making me crazy a lot that I cannot find a reason why it overheats with a same thermostat I have been using for 3 years.

------End of the Long Version-----

------Short Version------

FL1 1.8 Petrol suddenly starts overheating after 3 years of no heating problems. Even tho going with 100kph and radiator fans are on it is overheating.

No oil sponge, no coolant leak, no swelled hose.

Changed sensor (fans kicking in at the right time), thermostat (working normal), water pump, pulleys, belts, radiator cap (cap helped a little), radiator is clean, heater was disabled to test. Nothing has solved it. Bottom radiator hose is still ice cold.

Removed the thermostat, then it is not overheating at all, so we put a drilled thermostat, everything seems ok but I really cant settle without finding the reason behind.

-----End of Short Version-----

While I was writing I thought that it have never overheated while on first and second gear with high RPM, while testing on the road. But when I was at 3rd gear with a slight hill it overheated in 100 meters.

So please help me guys! Any suggestions or questions, hit me!

Hello, what type of thermostat you have ? is the old version located close to water pump or is the new one located close to radiator ?
...i mean this

Hello thanks for your reply, I have the one at the near back of the engine, I think it is the old one?

Yes it is old one ,buy one on eBay or wherever you want but to be complete with hoses .
http://www.ebay.co.uk/itm/FREELANDE...q1oAAOSw7NNUJDKS&_trksid=p2349526.m3874.l7936

And you need this remove the old thermostat and put it
http://www.ebay.co.uk/itm/K-SERIES-...lander&hash=item33bce00174:g:4xwAAOSw7KJXENl4

tonytherunner said:

Yes it is old one ,buy one on eBay or wherever you want but to be complete with hoses .
http://www.ebay.co.uk/itm/FREELANDE...q1oAAOSw7NNUJDKS&_trksid=p2349526.m3874.l7936

Click to expand...

Thanks for the suggestion Tony, I will try this ASAP. My mechanics also mentioned that replacing it closer to the radiator would solve it as it might not getting pressurized enough at the current place. Eventually, we preferred the easier solution: drilling the thermostat.

Do you have any idea how suddenly it became a problem after 3 years and 40,000 kilometers of smooth run?

For read www.myfreelander.co.uk/Engine/kengineprobs4.htm

Have you checked the coolant expansion tank? These can craze or crack around the neck = loosing pressure and overheating. Incorrect coolant cap?
Finally, when refilling with coolant are you bleeding the cooling system correctly? One bleed screw on the pipe from the thermostat to bottom radiator hose - it's about under the distributor - if you have a distributor that is! The 2nd is on the heater hose near where it goes into the fire wall.

htr said:

Have you checked the coolant expansion tank? These can craze or crack around the neck = loosing pressure and overheating. Incorrect coolant cap?
Finally, when refilling with coolant are you bleeding the cooling system correctly? One bleed screw on the pipe from the thermostat to bottom radiator hose - it's about under the distributor - if you have a distributor that is! The 2nd is on the heater hose near where it goes into the fire wall.

Click to expand...

Thanks for the reply htr! I am sorry I forgot about mentioning that we did bleeding like you described after every try. I bought a new radiator cap but couldn't find a expansion tank in stock. I do have some cracks at the top of the expansion tank but it seems like minor cracks. Could that be the problem?
I might send a picture of it later.

Glendir said:

Thanks for the reply htr! I am sorry I forgot about mentioning that we did bleeding like you described after every try. I bought a new radiator cap but couldn't find a expansion tank in stock. I do have some cracks at the top of the expansion tank but it seems like minor cracks. Could that be the problem?
I might send a picture of it later.

Click to expand...

The fine cracking around the filler neck will allow pressure to escape. This can result in coolant loss over time. I severe cases, the coolant can boil out the tank, in a large gush.

here is my old one,has severe cracking

Those are photos of it and it seems severe now that I look again. What do you guys think ?

Buy another one and change it , if is necessary buy expansion tank cap but i can testing if opening at 16 psi pressure ,and no buy low cost product is a waste of money.....

I made mistake to buy Allmakes expansion tank cap some time ago and is just a garbage.

I will definitely buy a new tank along with a thermostat replacement hose. I have already bought a new cap before. I will post updates. Thanks and cheers!

tonytherunner said:

I made mistake to buy Allmakes expansion tank cap some time ago and is just a garbage.

Click to expand...

This is spot on. The All makes cap on my TD4 won't hold 16 Psi. 10 Psi is closer to its actual hold pressure. It doesn't matter to me because the TD4 never gets to 100°C anyway. However a petrol Freelander definitely does need a cap that hold firm upto 16 Psi.

I got this one here: http://www.roverparts.com/Parts/PCD500030

tonytherunner said:

Yes it is old one ,buy one on eBay or wherever you want but to be complete with hoses .
http://www.ebay.co.uk/itm/FREELANDE...q1oAAOSw7NNUJDKS&_trksid=p2349526.m3874.l7936

Click to expand...

So... mystery continues:

I got new version thermostat hoses installed, and changed the expansion tank. Still overheats, however it cools down easily back to middle point. THen I unplugged the temp. sensor and with the cooling fans on there was no overheating.

Glendir said:

So... mystery continues:

I got new version thermostat hoses installed, and changed the expansion tank. Still overheats, however it cools down easily back to middle point. THen I unplugged the temp. sensor and with the cooling fans on there was no overheating.

Click to expand...

What do you mean by "overheats"?
The gauge showing high?. Or the coolant boiling over?
What thermostat do you have?

Nodge68 said:

What do you mean by "overheats"?
The gauge showing high?. Or the coolant boiling over?
What thermostat do you have?

Click to expand...

Gauge was increased to 3/4 for a while going uphill, then it was decreased to a very little higher than 2/4 when I let go the throttle while going downhill. I pulled over and checked, although gauge seems fine, expansion tank was nearly full (we just put half of it before the drive and bleed the air) and some coolant was spilled around the tank, radiator cooling fans were working.

Then I made cooling fans work nonstop by unplugging temp. sensor; water came down to half mark of the tank. drove with nonstop fans to home, no overheat occurred.

The hoses I got had a sealed house and thermostat built in. we checked if it was working ok by heating the vehicle up at the repair-shop, it opened the circulation at proper temp (by looking at the gauge)

I am sorry for my english, if I couldn't make anything clear, you can ask me faster over skype baran.tunc

my mechanics tells me that even tho no evidence of it, this seems like HGF and needs to be replaced as nothing else left that might cause overheat.