TR Register Forum

When we got home after the run down to Picton for Christmas lunch in the long door TR2 I found a layer of rusty film on top of the coolant and on the radiator cap.

My first thought was a head gasket problem although there are no head gasket leak symptoms. The car didn't use any coolant, the plugs are all the same tan colour and the oil is clean and clear. Clean the rust foam off and the coolant is clear of oil.

The coolant was drained, radiator flushed with fresh water and the block flushed via the bottom hose before refilling with fresh coolant. I also re torqued the head while the coolant was out.

I took the car for a 30-40km drive and the rusty layer has returned. Again no other ill effects, the car is going superbly, the coolant level isn't going down appreciably if at all and the oil and plugs are normal.

The engine was rebuilt by the previous owner Bob Cousins and sat in his garage for many years before I installed it in the restored chassis. The radiator was also rebuilt by Bob and also sat around for some years before being installed.

As bought the engine had a high port head which I left in place for 1200 miles to run the engine in. I then fitted a newly rebuilt low port head and have covered 1600 miles since the head swap. I retorqued the head after 400 miles. The engine hasn't shown any signs of head gasket problems.

Anybody else had a rusty layer on the coolant and what was the cause?

are you using green coolant

Yes. Have been for many decades in all my TRs. I've used Nulon and Penrite.
Is there a problem with it?

Often with hoses they have a wire coil to support the hose, particularly the input which is under suction. Ultimately they rust out and get carried into the motor where the wire continues to rust. Not a problem if all else is well.

my car does not use coolant










I do not check coolant level very often as car does not run hot or use water but i have same brown "cream"
under the cap and brown water on top. I drained and flushed the radiator and after time the brown is back, (12 months and 10,000 kms). Now past being concerned just living with it and assume minute amount of oil being picked up at head gasket as there is no sign of water in oil and no drop in coolant level after a 5000k trip.

As recommended by UK TR owners I bought a kit to test for CO2 in the coolant. A relatively cheap and, based on the UK TR owners recommendation, a highly reliable way of checking for head gasket leaks.

The kit uses a fluid that changes colour from blue to yellow when it detects CO2. I ran the test and the fluid didn't change colour meaning that there are no exhaust gases in the coolant.

In accordance with the instructions I had the engine running for about 6-7 minutes from cold and about 4 minutes with the thermostat open. It had air bubbling through the fluid including a few 30 second runs at reasonably high revs, maybe 2500-3000 (head under the bonnet so couldn't see the tacho). The temp gauge was about 190 when I stopped the test.

The rusty layer in the coolant is probably one of those random things that happens to annoy one.

Flushed my radiator again over xmas with Repco radiator flush and checked today ...........coolant is now clean and green after a few hundred klm. Only place I can think that the contamination came from is the oil way from the block to the head for the rockers. Possibly small amount oil was leaking into the water from there but sealed itself prior to cleaning the system ( nothing to do with rad flush)

Never used to believe in snake oils but I put Repco engine seal in my diesel jeep and it has stopped the nasty black puddle from leaking rear main seal. Pity it will not work on the TR.

Hi Peter we need the right ratio of water in and oil out other wise it is not a TR cheers Ken