HG ok, PRT 'ok', Bottom hose stone cold

I've been lurking around this forum for a few weeks, searching for what I thought were appropriate threads that may cover my issue... Nothing I found quite matches, so here's my Freelander woe to join countless others here

I made a short video to help explain:

YouTube

My wifes Freelander has it's head gasket changed about 6-8 weeks ago, was ok maybe for about a month (though wasn't used very much in that time) then my wife noticed steam escaping from under the bonnet. Sure enough, steam was coming out of the pressure relief valve in the header tank cap.

The PRT mod thermostat was changed for a brand new one, assuming the old one has stuck in the shut position, yet the water does not appear to ever circulate through the rad. The bottom hose, even after a 'brisk' run (i.e. giving it a bit of a caning to get the temp up!) the hose remains stone cold.

The top hose feels pressurised and obviously extremely hot when the engine is up to temp. The temp gauge never reports anything else other than 1/2 way, water feeds into the expansion tank via the small pipe off the top hose. The air has been bled from both the heater matrix screw (black plastic screw in the top small hose going into the bulkhead) along with air being bled from the metal pipe that runs along the rhs of the rocker cover/engine block (this air bleeding comment was completely skipped in the video!).

I'm at a loss as to why the thermostat will not open and was wondering if there is any way to mod-again these PRT mods to ensure the thermostat opens to get the radiator to do it's work...

Suggestions much welcomed!

I'm not over familiar with your engine however having spent ten years of my life building and repairing radiators and all the diagnosing of cooling system issues that goes with it here's my ten pence worth.

First thing we would do was remove the thermostat all together from the housing and run without one. I know you don't have a stat housing but if you can find a way to run without the stat this is the starting point.

If the problem remains then rather than a flow test which can be inaccurate, you would need to remove the radiator hoses, blank off the bottom, pull the fans back and fill the radiator with boiling water. We used to boil the water in a metal watering can! You can then feel for cold spots across the radiator core. Big sections of a cold core and your radiator is blocked.

Have you spun the engine over with the top hose disconnected to see if the water pump fires it out at a rapid rate. Have had occasions where the water pump veins are slipping on the spindle. Generally no noise is given off so you don't know it's happening!

An overheating temperature top hose, and a stone cold bottom hose can only be a circulation issue, and there's not too much it can be.

To test therm presuming they still work this way, cool it then dunk in boiling water it should open/close..

Sounds like water pump the tbh to me..

I had a similar problem, turned out to be an airlock.
Was eventually diagnosed and fixed by a main dealer, which was the nearest place to limp to when it eventually started venting while driving!
(This is after other garages had diagnosed HGF)

bukko said:

I had a similar problem, turned out to be an airlock.
Was eventually diagnosed and fixed by a main dealer, which was the nearest place to limp to when it eventually started venting while driving!
(This is after other garages had diagnosed HGF)

Click to expand...

Didn't think of the obvious doh ur prob right...

I have just overhauled the top end of my FL1 and it is a 1.8 petrol. I ran it initially with no thermostat in the original housing for the purposes of cleaning the cooling system using a strong citric acid solution. This was then flushed out twice with deionised water. Finally I fitted a PRT thermostat arrangement and refilled the cooling system with a 50% solution of red OAT coolant.

My point is that each time I ran the motor while doing this work the bottom hose took the longest time to heat up. I let it idle each time until the radiator fans came on. They only came on at a low speed, but they did come on. With the PRT it took even longer to heat that bottom hose.

I suspect that your radiator could be partially blocked. Other threads where cooling issues have been discussed also mention a careful inspection of the coolant tank. Look for any signs of cracking around the neck area or perhaps a faulty cap on the tank.

A contributor called Tonytherunner also had a cooling system issue and found an unusual problem. Look at his posts and see if they help.

Good luck!

It is common for the bottom hose to feel cold, especially with the 1.8.
My V6 Freelander bottom hose temperature never climbed more than 10°C over ambient temperature. The rad is the same for 1.8 and 2.5 V6. The V6 dumps twice as much heat into the coolant so it's no wonder the bottom hose is cold with the 1.8.
The only way to test the PRT is with some revs. Once the engine is hot (10 to 20 minutes at idle) give it a few good rev session over 4500 rpm. This should open the Pressure Relief valve and should pass enough hot water to the radiator to warm the bottom hose.

Ok... I've been back out to the car to see what's what. Popped off the top hose, started the engine up, water pouring out of the hose, clearly indicating the water pump is working just dandy.

Refitted the hose, popped out the PRT, took to kitchen sink, boiled kettle. Drizzled enough water in the straight through inlet (of the Y end) to get heat into the core of the thermostatic valve, eventually it opened, sort of sealing off that in-line port, allowing water to be fed in the side-Y port that drained freely through the now-open in-line port that connects to the bottom of the rad.

So I've read before the 1.8 rad is the one used on the 2.5 also, so it's perfectly adequate to cool the engine, /when/ it's brought into play by the PRT opening.

The only thing that concerns me about leaving the engine idle for 20 mins, then giving the loud pedal some welly, is that that should've happened the last time I drove the car like a screaming banshee. 'Cept the bottom hose never got anywhere near luke warm, let alone hot. All the while, the rest of the pipework looked like it was about to burst...

I'll put the PRT back in, give it another blast.

Know anyone who wants to buy a 52 plate Freelander, South Wales?? Going cheap!

So the bottom hose is the outlet? ( I've no ides its something I've never checked), ifso maybe its working great and its cooled as it should?, if not is it possible for a garage douggie to have got it going the other way?, ( I'm guessing not but I've prob seen worse done at a garage)..