coolant leak KV6

[Mr Toad]

Hi All,

I can't remember when I last posted about this problem and thus can't find the thread. However, I still have the problem of a coolant leak which I cannot find. I have checked everything there is no exterior leak. I borrowed a pump for the cooling system pumped it up to 14lbs and the needle remained rock steady. After travelling about 70-80 miles I have had to put in about 350ccs of coolant. The car is performing ok and I got a mechanic who I know to have a quick look and his view was that it was not HGF, but where on earth is the coolant going. I am nearly at the end of my tether with this problem and after nearly a year! In spite of what my mechanic and Simon said on this forum I still think that it must be HGF I don't think it can be anything else, can it? Any bright ideas please.

Martin

[SD1too]

Martin,

23rd September (https://www.the75andztclub.co.uk/forum/showthread.php?t=298187) was your last post on the subject of coolant loss.

If you select 'view public profile' under your user name to the left of your message, choose the 'statistics' tab, then 'Find all posts by Mr Toad' you will get a list of all of them.

Simon

[Yorkshire GOC]

If i was suspecting HGF - albeit on my 1.8t - i would be looking for the following

1. Brown mayo on the dipstick

2. Brown mayo under the oil filler cap

3. Pressure escaping from a cold system - ie after a good thrash - say 10-15 miles at motorway speed - leave till next day and open expansion tank cap - if there is a loud sound of escaping gas then that points to exhaust fumes in the cooling system and points toward HGF:shrug:

Did your mechanic do the chemical CO2 test on the coolant - not sure if it gives false positives - but it sems to be in widespread use to identify exhaust gases in the coolant.

[charlie 22]

Hi All,

I can't remember when I last posted about this problem and thus can't find the thread. However, I still have the problem of a coolant leak which I cannot find. I have checked everything there is no exterior leak. I borrowed a pump for the cooling system pumped it up to 14lbs and the needle remained rock steady. After travelling about 70-80 miles I have had to put in about 350ccs of coolant. The car is performing ok and I got a mechanic who I know to have a quick look and his view was that it was not HGF, but where on earth is the coolant going. I am nearly at the end of my tether with this problem and after nearly a year! In spite of what my mechanic and Simon said on this forum I still think that it must be HGF I don't think it can be anything else, can it? Any bright ideas please.

Martin

I had a similar situation, kept having to top up the coolant for a very long time even got my mechanic do a pressure test and found no leaks. Turned out to be air in the system and only worked its self out by months of topping up the system.

[Gunnerhavesome]

Hi All,

I can't remember when I last posted about this problem and thus can't find the thread. However, I still have the problem of a coolant leak which I cannot find. I have checked everything there is no exterior leak. I borrowed a pump for the cooling system pumped it up to 14lbs and the needle remained rock steady. After travelling about 70-80 miles I have had to put in about 350ccs of coolant. The car is performing ok and I got a mechanic who I know to have a quick look and his view was that it was not HGF, but where on earth is the coolant going. I am nearly at the end of my tether with this problem and after nearly a year! In spite of what my mechanic and Simon said on this forum I still think that it must be HGF I don't think it can be anything else, can it? Any bright ideas please.

Martin

I had the same issue on and off for 2 years and even drove the car to the Pyrenes and back twice in that time. I was stumped and thought HGF but could not find the leak. Eventually one morning while refilling the header tank the water started to come out at the back of the motor as fast as I was putting it in. Unfortunately for me it was on my 3rd trip to the Pyrenees when this happened. It turned out to be the water pump had failed and this cost me my first born child to fix but as the car had only done 76000m it was due for new timing belts anyway so the pump and belts and tensioners where done as well as new covers.
So my suggestion is water pump.

Hope that helps.

[Mr Toad]

Hi All,

Happy New Year everyone

I'm afraid I still have the coolant leak. There has been no real change so it looks like the heads are going to have to be removed.

However, I was speaking to a garage proprietor today and he gave me a product called "Rad Fix". He says it is non clogging and he has used it many times with good results. The product is not generally on the market it is supplied to garages and large transport organisations apparently.

It is made by a company called Tough Technology Products and I have spoken to them and they confirm that the product is not like all the other products on the market but they obviously could not guarantee that it will work but they said it can be easily flushed out if it doesn't.

Anybody had any experience of this product as I am very tempted to give it a try.

Martin

[Yorkshire GOC]

Firstly 2 things to bear in mind - HGF on the V6 is a rare event and any sealant is viewed by many as the devils device - causes more problems in the long run than it solves. The line of thought is find the leak.

Does the car still run OK ? Could it be the Inlet Manifold Gasket - i had this on a 1.8t and the leak was small .:shrug:

[Mr Toad]

The car runs perfectly and in a previous thread I explained that I have replaced the inlet manifold gaskets TWICE to eliminate that source of the leak.

For the life of me I cannot find any leak I doubt that I can spend any more time trying to find it.

I now have to make a decision either to add the Rad-Fix or take the heads off. As they say the stuff is non clogging it may be worth giving it a try. They say it can be flushed out if it doesn't!

Anyone else got any views please?

Martin

[trikey]

You may not find the leak even after fitting new head gaskets, a local member has the same problem, water level dropping randomly, he has had the head gaskets replaced by a reputable garage, I have changed the stat and the inlet gaskets, its had a new oil cooler and I cannot locate the issue!

[SD1too]

I now have to make a decision either to add the Rad-Fix or take the heads off.
Martin; if Rad-Fix is "non clogging" and "can be flushed out" then how can it seal a leak in the long term? Think about it.
The second point about products like that is that they do not eliminate the problem, they "paper over the cracks".
The third point is that they're designed for completely non-technical owners which you clearly are not.

Removing the heads will be a waste of time and a lot of money. You will not have head gasket failure on a KV6.

Have you ensured that the two plastic clips on the straight pipe in the 'V' are both pushed fully outwards so that they are in close contact with the water pump and thermostat housings? A small leak in the 'V' can evaporate leaving little trace.

Renewing the flattened 'O' ring seals on my original expansion tank cap made a big difference. Have you done that?

Simon

[charlie 22]

I had a problem for months with dropping coolant levels to the point the i was getting really concerned. No obvious leaks and even got my garage to pressure test the system and came back ok. Would top up check a phew days later and coolant gone from the header tank had to put in quite a lot to bring back to the max level on the header tank. With the help and patience of the members it turned out to be an air lock in the system. Now that it has been cleared the level has stayed consistent between levels in the header tank.

Sent from my SM-G977B using Tapatalk

[SD1too]

I had a problem for months with dropping coolant levels ... No obvious leaks ... With the help and patience of the members it turned out to be an air lock in the system.
:wot:

An excellent point Charlie, I had forgotten that one. :duh:

Martin; has your cooling system been drained and refilled recently without using the proper MG Rover procedure?

Simon

[Lord of Hog]

This may sound daft but the smell of OAT is pretty unmistakeable. Get the car out of the wind and preferably in an enclosed space, stick your nose under the bonnet and have a good old snuffle. If there's a trace of it in the V you'll notice it (particularly with a slightly warm engine).

Secondly please remember that a lot of the points with the greatest potential for coolant loss are a) difficult to see and b) warm, meaning that your evidence is going to be nothing but a pink stain and will be hard to see. Hence the usefulness of the sniff test.

Thirdly, based on my own experience if it's not the thermostat O-rings, the thermostat straight pipe, the inlet manifold, the radiator or the plastic elbow on the radiator it's likely to be an air lock. Some of the coolant channels inside the engine are extremely narrow (hence their susceptibility to clogging with RadWeld and such) and can take a long time to give up any air that enters.