Tamd41a Coolant leak

[bowler]

Hello all.

Just back from a nice trip along Irelands north coast and a hop over to scotland.

I had recently replaced the turbo to exhaust manifold gasket as it appeared to be leaking coolant. Sadly it appears that my leak still exists, or perhaps I had two!

It appears to be tricking down from an area above or behind the oil cooler. Damned if I can see anything more than that. I have some remains of UV dye from my first test still in the system.

It only leaks at high rpm. No overflow from expansion tank.

I have read many posts online and they seem to point to a head gasket or exhaust manifold gaskets or perhaps the heat exchanger entry and exit pipes or water pump. I have had a quick check and the exhaust manifold nuts seem tight, at least those I can get a spanner on!

I have another trip planned for the first week of August and would love to resolve this before then but getting good engineers over here is a challenge.

Any expert tips or advice on how to proceed DIY style? Not sure if presurinsing the system would tell me more than i know already.

This trip needs to go ahead so all advice welcome.

D

 

[Mr Googler]

Exhaust manifold seals. You could check the exhaust manifold bolts are tight. I had a coolant leak the was going along the top of the engine, down the back, hitting the bell housing and running left and right! A few loose manifold bolts. Nipped them up and leak stopped

 

[bowler]

Hey Mr G.

Enjoying the boat thread of yours. Almost there!

Did yours only leak at high rpm?

D

 

[Mr Googler]

Hey Mr G.

Enjoying the boat thread of yours. Almost there!

Did yours only leak at high rpm?

D

yup and cheers!

I found it with the dye. Engine block below showed signs of staining too so probably been going on for a while. Could be thermostat to manifold seal too….oil cooler is right underneath it

 

[bowler]

Grand so. Maybe I will pull the heat exchanger off for a closer look.

D

 

[Plum]

Hello all.

Just back from a nice trip along Irelands north coast and a hop over to scotland.

I had recently replaced the turbo to exhaust manifold gasket as it appeared to be leaking coolant. Sadly it appears that my leak still exists, or perhaps I had two!

It appears to be tricking down from an area above or behind the oil cooler. Damned if I can see anything more than that. I have some remains of UV dye from my first test still in the system.

It only leaks at high rpm. No overflow from expansion tank.

I have read many posts online and they seem to point to a head gasket or exhaust manifold gaskets or perhaps the heat exchanger entry and exit pipes or water pump. I have had a quick check and the exhaust manifold nuts seem tight, at least those I can get a spanner on!

I have another trip planned for the first week of August and would love to resolve this before then but getting good engineers over here is a challenge.

Any expert tips or advice on how to proceed DIY style? Not sure if presurinsing the system would tell me more than i know already.

This trip needs to go ahead so all advice welcome.

Sorry to hear of your problem and can't help specifically but for investigating collant leaks and checking after doing work I recommend you make a pressure tester. I've used mine many times. I T'd into one of the 8mm degas hoses that go to my header tank together with a pressure gauge, a shrader valve and a bicycle pump so I can apply 10psi and slowly go round with a morror, torch, etc. This will not help for the leaks that only appear when hot but has certainly helped me to find leaks that only appear when under pressure.


www.solocoastalsailing.co.uk

 

[bowler]

Cheers Plum. Nice simple system.

D

 

[alt]

Exact same issue on one of my KAD300's - it was the exhaust manifold gaskets (3 of them!).

Obviously replace all 6, and depending on your access, few other gaskets too.

In all honesty, it wasn't too hard of a job and no special tools required... just a little patience.

The thing that scared the crap out of me.... when all back together and ran for the first time, the gaskets were leaking! (despite torqueing to recommended specs). I was depressed and didn't want to tighten more incase I snapped something. Took the risk and tightened up all the bolts another 1/2 (approx.) turn and no more leaks.... all like new! It makes sense to re-check the torque after a few hot / cold cycles.... issue on the KAD300 is not all of the bolts (ie. none!) are accessible when everything is back together.

 

[bowler]

Cheers alt. Good to know and glad you got it sorted in the end. Initially I thought it was still coming from the turbo gasket I had just replaced so I know the feeling. Will investigate the exhaust manifold gaskets first then.

 

[bowler]

Hi again all.

I have ordered the manifold gaskets. Plan is to pull heat exchanger and check if all bolts are tight on the manifold. If they are, then turbo off and exhaust manifold off I assume? The turbo/exhaust manifold gasket was recently replaced so shall I reuse it? Also, any other bits I should replace while in there?

Cheers,

D

 

[bowler]

Ok.

Got everything off. Some craic as they say.

Some gasket material is stuck on some of the surfaces on the head. What's the best way to clean this off without letting the crud into the cylinders? Just being cautious.

D

 

[bowler]

Well. Not the result I wanted. Cleaned the faces up. Put it all back together. Three of them are leaking. I torqued them up to 40, and a little more after seeing the leaks. Now I am stumped.

Thoughts anyone?

 

[Mr Googler]

I read somewhere about making up a long flat board and covering with wet and dry sand paper.

you then run the manifold over it to get the mating surfaces flat.

@volvopaul is your best bet

 

[bowler]

Mr G!

Thing is I was eally careful with the cleaning. Spent about 5 hrs cleaning alone. Very careful as well.

Odd thing is, I left for a bit to clear my head and ran it again in gear when I came back. Now it appears to not be leaking? Or if it is not noticable like before, and I have dye in it for checking. What the fudge?

I nipped the nuts a smidgen more and will test run tomorrow. My head is fried.

 

[Mr Googler]

If it doesn’t leak….leave well alone!

a full chatt blast will reveal all ??

 

[QBhoy]

Hi. Two things. Although you say it’s not leaking from the header tank. If it was a cylinder head issue, it would only show leaking from there when running high rpms usually. The gas would leak into the cooling system and pressurise it enough to open the relief mechanism on the header tank cap. You’d need to watch it as you run at high rpms to see it doing this. Won’t usually do it at idle or lower rpms.
if it’s not that..I see the leaking fluid seems to be right below that coolant bleed fitting. Any chance that’s not seated properly ?

 

[bowler]

Hi. Two things. Although you say it’s not leaking from the header tank. If it was a cylinder head issue, it would only show leaking from there when running high rpms usually. The gas would leak into the cooling system and pressurise it enough to open the relief mechanism on the header tank cap. You’d need to watch it as you run at high rpms to see it doing this. Won’t usually do it at idle or lower rpms.
if it’s not that..I see the leaking fluid seems to be right below that coolant bleed fitting. Any chance that’s not seated properly ?

The new leaks were definitely from the exhaust gaskets. It occured to me that on the 3 leaking cylinders when I removed the manifold the whole at least one of the 2 studs came out as the nut was corroded onto the stud. A mechanic has suggested that it might be worth removing those studs and getting the nut off, cleaning up the studs and reinserting before fitting with a new nut, as the current set up may not be allowing me to torque them up correctly.

 

[Plum]

The new leaks were definitely from the exhaust gaskets. It occured to me that on the 3 leaking cylinders when I removed the manifold the whole at least one of the 2 studs came out as the nut was corroded onto the stud. A mechanic has suggested that it might be worth removing those studs and getting the nut off, cleaning up the studs and reinserting before fitting with a new nut, as the current set up may not be allowing me to torque them up correctly.

If when those studs were originally fitted they were screwed in to the limit if their threads before the nuts were fitted, then now your nuts are rusted onto the studs, when you re-insert and you torque up all you are doing is running the stud up to its thread limit without applying the correct clamping load onto the gasket so minimal chance of fixing your leaks. Your mechanic is quite right.

Www.solocoastalsailing.co.uk

 

[alt]

The same thing happened me, they started leaking when replaced.

I ran the engine up to temp and let it cool back down, tightened each bolt maybe 1/4 turn each and viola... no more leaks.... have put about 15 hours on the engine (at 3000 RPM with the odd quick blast to WOT).

-Edit- Just seen your issue re. studs. 2 of my studs also came out, BUT, the nuts weren't seized (they came off easily after). That said, I cleaned ALL of the stud threads before re-applying the nuts.

 

[bowler]

Thanks folks. This is all music to my ears. Thursday night was grim. I will be reassembling early next week as I have somehow lost one of the studs so had to order a new one from Royston. Fingers crossed!