Where's the coolant gone?

My F has been losing coolant over the last 3 weeks.
I was first aware of it when on turning on the ignition the low coolant alarm sounded.
Needed nearly a litre to top up, then did a 20 mile run with no probs. & a few since.
Not used the car for 6 days & the expansion tank was empty- took another ltr. to top up.
The HG was done 10 months ago & oil is ok,, plus a new cap fitted.
Seems that it must be a hose or rad. problem, so will have to have a look over the W/E.

My problem was the inlet manifold gasket. These silicon gaskets become hard over time. At first I was aware of an occasional external leak with a small pool of coolant collecting under the engine. Then I noticed a bit of steam from the exhaust on start up - a small amount of coolant had seeped into one cylinder...#4 as it turned out when the gasket was changed. No permanent damage had been done as I stopped using the car as soon as I realised where the coolant was going - internally! You may have a different problem of course but check your exhaust for steam on start up and the engine for any rough running. Also if there is a marked drop in the header tank level as you start up, the inlet manifold gasket is probably the culprit. There is a school of thought that the plastic manifolds are more prone to distort than the alloy ones but my plastic manifold was straight.

Richard

I would suspect the head gasket and coolant is leaking into one of the cylinders, or from the inlet manifold into an inlet port, unless there is an obvious external leak, but a litre of coolant is a lot.

A litre does sound a lot it could well be a pipe or rad as you suggest.There is the pipe that reseals it'self I'm sure David has done a thread on it somewhere.

I had a plastic inlet manifold on my ZT engine and it leeked quite a lot,I never lost a litre in a short time from the inlet manifold.The viton gasket does help and lasts far longer than the oem rubber one.I swapped out the plastic manifold for the alloy one last month hopefully no more leeks.

Old inlet manifold

Happy leek free new one

some coolant leaks are not always easy to find when the engine is still..........at my work we build modern engines,we connect them to a water supply and check for leaks, it is not always obvious to see a leak untill the coolant preasure is pumped up a little.............We use a small hand pump that fits to the top of the rad................about 10psi is all we pump in...............The coolant preasure pumps are used by most mechanics and come with adaptors to fit different coolant systems...the engines we build are preasurised to 10psi and inspection for leaks is observed............we also check the presure gauge for a presure drop................this will indicate any internal leakage........i have made my own using exspantion tank tops and bolt on tyre valves............simply pump with a bicycle pump...........presurising the coolant system should be done at owners disgression :woowoo:

Didn't you pay a well known mobile MG Mechanic for some work done?

I'd start by checking things over yourself.

I'd suspect the waterpump with that amount but that is usually done the same time as the head gasket.

Rad or underneath coolant pipes would be next on the list.

You could do with just starting the car from cold and then jacking it up and watching from underneath. If water is going with revs then maybe waterpump.

I'm outta the MG game but have had a few coolant stories of doom myself including the expansion tank potnoodle / mcdonalds saga.

Good luck on getting it fixed.

Hopefully some new rubber will fix it.

Oh errrr
BRING ON THE GIMP

Start at the front and work back checking the radiator then the hoses and pipes for leaks. "Elsie" was losing a bit and it was only o the MOT whilst nosing under the car that we spotted a weep from the fairly new S/S pipes to teh rubber hose joints. Extra clip added and it seesm to have stopped it but still losign a tiny bit somewhere as had to top it up 1/4" before going down the Santa Pod on Saturday. Mind you had not checked it in several weeks :oops: .

The best way to find a leak, I found, was to give the car a good blast, come back and lift the car.(ramps, axle stands) and then switch off, and get underneath with a good torch. Check under the inlet manifold, under the expansion tank, and the bottom of the engine for drips. Obviously the rest of the cooling system needs looked at too. /underfloor pipes and rad.
If you're not seeing obvious signs on the ground under the car it's likely to be evaporating on the hot engine.:shrug:

Problem solved :woohoo:
It turned out to be the rad. that was rotten all along the bottom.
As it was the original one fitted, I suppose 15 years life aint bad :yesnod:
Should get new one tomorrow & be back on the road soon.
Thanks for all the advice.

Forrester wrote: Problem solved :woohoo:
It turned out to be the rad. that was rotten all along the bottom.
As it was the original one fitted, I suppose 15 years life aint bad :yesnod:
Should get new one tomorrow & be back on the road soon.
Thanks for all the advice.

This seems too be getting more common with age. Found the same issue when we got "Elsie" the listing said losing coolant suspected HGF and ti was the radiator.

Inspected my rad by glancing through nooks and crannies,it looked like new.......................Then i took off the front bumper and discoverd it had bowed at the bottom and looked a little worse for wear.....................although its not leeking santas bringin another