Steel seal

[Volvoluke]

Hi Everyone, ever since I've owned my car 940, owner for 5 years. It has had a minor external head gasket leak just below the exhaust manifold. It has never caused a problem so I've just left it alone. However I read recently that this can lead to pitting/erosion of the block and head due to pressure escaping. Any thoughts??
I have considered using 'steel seal' as I'm sure this would stop the leak. My question is can steel seal have a negative effect on anything else?

[Laird Scooby]

First thing to be sure of is that it's the head gasket? Could be the short hose between the water pump and the head leaking and the coolant is being blown back by the fan.

I'm not the right person to ask about sealants as i prefer to avoid them - regardless of whether you love them or loathe them, they are only a temporary measure and won't cure the ultimate problem.

For example, on my 760 i have a slight weep from my radiator, i was going to buy another that was listed on ebay but it sold while i was waiting for the funds to arrive for it.
Now it looks like i'll have to chuck some Radweld or similar in to tide me over until i find another. Had it been on my other car, i can't use any form of sealants on that as it will block important water channels, particularly around the throttle body, and the cold running valve that increases the idle speed during warm up.

Either way, sealants can cause unwanted blockages so be careful if you do use K-Seal, Steel-Seal or anything similar. Would be better to find and fix the cause of the leak first though.

[AndyV7o]

Just do the head gasket if sure that is at fault.
Steel seal does reputedly work, at least short term, but do you want something that can seal a head gasket under pressure and heat passing through the small water passages, heater matrix, and radiator...?
Ive used K-seal before for radiator leaks in a couple of cars and one of them lost a significant amount of its ability to heat the cabin afterwards.

[NI_Volvo_Nut]

Steel Seal is wonderful stuff, used it a few times now, one time was on a 1.9 CDti Zafira with an external head gasket leak, I could actually watch the leak stop as the sealer done its job.

[kelvinp]

Originally Posted by AndyV7o

Just do the head gasket if sure that is at fault.
Steel seal does reputedly work, at least short term, but do you want something that can seal a head gasket under pressure and heat passing through the small water passages, heater matrix, and radiator...?
Ive used K-seal before for radiator leaks in a couple of cars and one of them lost a significant amount of its ability to heat the cabin afterwards.

I've got an MG ZT and there is often talk of suspected head gasket failures on the K series and people having used K-seal or similar to 'cure' it and it often ends up wrecking the engine as it ends up clogging up water ways, heater matrixes etc and is a pig to remove totally. It often ends up more work to remove it all than it would have done to just replace the head gasket in the first place.

It's also only any good for water leaks in the head gasket - if you've got a blown head gasket between cylinders for example then it would not help.

I have used K-seal on a bus engine recently to deal with a slight frost crack on the block and it did work here, plus there's less of an issue with small water ways and things.

[classicswede]

I would only use the likes of steel seal on a disposable engine/car

I have seen gaskets leaking down the side of the block a few times. If left like that the block can corrode in that area so best to get it sorted.

Its not a long job to do the head gasket

[Laird Scooby]

Originally Posted by kelvinp

I've got an MG ZT and there is often talk of suspected head gasket failures on the K series and people having used K-seal or similar to 'cure' it and it often ends up wrecking the engine as it ends up clogging up water ways, heater matrixes etc and is a pig to remove totally. It often ends up more work to remove it all than it would have done to just replace the head gasket in the first place.

It's also only any good for water leaks in the head gasket - if you've got a blown head gasket between cylinders for example then it would not help.

I have used K-seal on a bus engine recently to deal with a slight frost crack on the block and it did work here, plus there's less of an issue with small water ways and things.

Most of the time on the K-Series (whether 4-pot or KV6) the HGF is only a symptom of a bigger problem elsewhere. Usually the wet liners have been positioned wrongly so they're either not proud enough or too proud on the block height.
Or perhaps a previous garage has changed the HG and turned the engine over while the head has been off without the retainers in place so the liners have moved.
Another favourite is the thermostats on the K-Series, the one behind the block at the bottom on the older 4-pots or the one in the plastic housing in the Vee under the inlet manifold on the V6 models.
Both are prone to leaks for variosu reasons and sticking shut too. In the case of the older 4-pots, they open too quickly when up to temperature which can thermally shock the engine causing disotortion and you've guessed it, HGF.

As you rightly say about K-Seal though, it blocks up more than it should and causes more problems than it should.

[Volvoluke]

Thanks for the replies, seems the majority think it's a bad move. Maybe it really is best to just change it. My only concern is where it's been on going for so long the head is bound to be corroded 😐

[brutusmotorsport]

steel seal works well. put in a wagon at work to cure small leak few years ago. still good 150.000 miles later. but choice is yours. yes there mixed feelings on this but choice is yours.

[AndrewBrown]

I have only ever used it once on a 1985 VW polo and It blocked up the heater matrix so the heater was cold all the time

I only found out when I removed the hot feed pipe to check the heater valve operation I found the pipe entering the matrix to be solid with the stuff and the valve was working ok

I flushed the matrix back and forth a few times and it cleared out