does this sound like an air lock?

[sawman]

Had the chim in for an MOT at a local trusted garage. it passed with no issues but the guys noticed a small coolant leak in the bottom hose - duly fixed with a couple of new clips.

yesterday I noticed that the car got up to temp on the gauge a bit more quickly that usual in traffic to work, but later on a run to another site all settled to pretty much normal (if slightly higher than usual)

Today I had a 35 mile commute and so while the weather forecast for the next few days is wet, I thought I'd take the TVR again, after.a couple of miles of slow traffic (gauge showing 100) it seems to be getting warm, I just get on to the dual carriage way and a puff of steam vents through the bonnet slash on the off side. I pulled over but couldnt see any leak. (whilst still near home I nursed the car back home and reverted to the tin top for the commute)

Poking around under the bonnet tonight there is no sign of dropped coolant under the car, or in the engine bay, I did note that only 1 fan came on until i fiddled with the connectors, which encouraged the both of them to work.

So just thinking about causes of the steam puff/overheating, I wondered if the guys at the garage didnt use the correct technique to top up the coolant after fixing the leaky connection and so air lock has developed, or was it just that 1 fan wasn't working that lead to things getting hot? The rad is only 6 months old so don't think thats the problem.

I'll have a proper look at it again on friday,

[Boosted LS1]

Have you lost any coolent?

[sawman]

Well there wasnt much in the expansion tank, i havent looked in the swirl pot yet.

[Aussie John]

Could be the radiator needs bleeding.

[TarquinMX5]

It's a good bet there is, or was, an airlock and the correct top-up method is set out in the handbook. If it hasn't happened before it would have to be quite a coincidence for it to be one of the fans causing it, the chances are that the fan was like that beforehand.

Pressure cap?

[sawman]

I’ll give the fan connectors a clean, maybe a new pressure cap would be good idea, my amusement for my next day off is bleeding the system

[TV8]

My 1st Chimaera went through a couple of radiators due to the tightness of the feet into the fibreglass body. Check there even if the rad is new.

Also, wrap some kitchen roll around the blue cap, that will tell you if anything is coming out through the cap. It will get wet or damp.

For air locks, check the heat coming out of the heater. If you get all of the air out, it should be very hot.

[Steve_D]

It may be that they did not know the expansion tank should be almost empty when cold. If they put too much in then your puff of steam was the system getting itself to the correct level. Also they may not have bled the rad.

Steve

[QBee]

And also, to my mind you gave away the issue in your original post = these cars need both fans working if sat in traffic.
My first response to comments like yours is always to check that both fans are working.

I would undo the brass screw and top up the coolant, make sure both fans are working, and test it in traffic.

[Classic Chim]

If in doubt flat out was what I was told on the speedway bike as a kid 🤣
So I’d have someone who reads up bleed the system again, I agree it’s likely be overfill of the expansion bottle if it came out that side vent area.

[sawman]

THanks all for confirming.
I’ll come back if things persist....

[sawman]

H'mm havent got very far - what the best tool to get the brass plug off the swirl pot - I havent found anything in the garage that quite cuts it. I had a couple of wood chisels but they are not thick enough to fit snugly in the slot so slip with any torque. It turns out my spade is a shovel so thats no good either.

feels like its pretty stuck,

[Classic Chim]

Long reach flat head screwdriver will do it usually. Place screwdriver into the slot but from the side, gives you lots of leverage to turn it.

[sawman]

i guess it needs to fit the slot snugly - is it any easier if the pots warm?

[nawarne]

When I had my Chimaera, I used an electricians bolster.

The 'handle' had hexagonal flats, so was able to get an open ended spanner to fit and use a bit of tube over spanner for leverage. Always sprayed some release fluid on first.

Nick

[Sir Paolo]

I use a bicycle spanner - the type that is flat with different sized bolt holes punched in it.

It fits snugly in the plug slot, and is wide enough so that you can apply force with both hands

[QBee]

I am with Classic Chim on this - got my biggest flat bladed screwdriver out and inserted it horizontally from the side.
But mine had been off about six months ago, so I wasn't expecting problems and didn't get any.

My TVR expert uses a socket set to get them off - he has a socket in his set that is a very big screwdriver blade, which fits perfectly. Worth getting one I think. But no idea where from

[sawman]

Thanks chaps, first part of the job done, had to get some coolant so picked to a long flat blade screwdriver.

Managed to squeeze a couple of litres in. Just waiting for it to cool off again. Did notice a bit of steam from nearside of rad’ top hose clip seems tight but i’ll check again when cool. Took ages for the temp needle to move much with the heater on full but fans kicking in at normal temp and cooling off well.

[QBee]

If you want to check for leaks, you can do it by pressurising the system. But it needs special kit.
I watched my TVR guy test mine.

Engine cold and turned off, he got out a thing like a bike pump with a tube and a pressure gauge on it, and at the end of the tube there is a thingy that goes on in place of the blue cap on the expansion tank. He then pumped the cooling system up vigorously, and he saw the pressure dropping away. Mild panic, because he couldn't see a leak, and has for some time wondered if my block was porous, but in the end I stuck my head under the car and told him that water was pissing out of the chassis rail my side!!

We then found the leak, at the inaccessible hose connector close to the bottom front of the block on the passenger side, and he fitted new clips to solve the problem.

[TarquinMX5]

Rubber or silicon hoses? I've found the latter can sometimes be a pain to get to seal properly, especially on first fit, unless decent hose clips are used; I've also seen jubilee-clip type ones overtightened on a silicon hose, resulting in it splitting the hose.

The small bore pipe at the base of the expansion tank can clog up if the coolant hasn't been changed regularly, causing a few issues. Also worth checking that the radiator bleed screw has its fibre washer fitted.

I use an old chain oil-filter removal tool for undoing the brass plug, the metal 'handle' is ideal for the job.