Lack of coolant changes?

[Will]

Have been stripping down a 190E for a head gasket replacement and cleanup just recently.

Took the head off today and you can clearly see where the gasket has breached the waterway and into the cylinders on the back two on the exhaust side:

What's more interesting is to see that the waterways for the affected cylinders were quite badly furred up as well (notice the 'missing' holes ) I'm guessing due to neglected coolant changes over the years, and/or topping up with plain hard tap water.

It had a water pump and thermostat about 5 years ago IIRC when I had a brief squint through the service history. Perhaps a cry for help a bit too late.

I'll certainly be cleaning it all out properly, checking the waterways on the block and flushing the heater matrix and radiator out before it all goes back together. And checking the head for trueness, although I feel that a very light 'facing'/skim would be worthwhile regardless in this instance?

Will

 

[LTD]

Could it be have been due to an incorrect torquing procedure ?

 

[Will]

Could it be have been due to an incorrect torquing procedure ?

No, it's blocked due to furring. I don't think the head has been off before.

I'm pretty sure that the gasket leaked because it was overheating, because the waterway was becoming blocked

So - the morale of the story is - don't neglect the coolant changes, and make sure you use distilled water and proper coolant

I'm quietly pleased that when I replaced the coolant on the CLK back in the summer, I used MB coolant and reverse-osmosis water

Will

 

[LTD]

Is this only intrinsic to areas of hard water ?

Fortunately, in Scotland we have 'soft water' but I always want the coolant changed every two years (with brake fluid).

It's always easier and cheaper to change fluids than stripping because you didn't.

 

[Will]

Think of it in another way:

Take a small compartment (the little cooling passage). Block it off, fill it with water, heat it up to boiling point - keep heating. I guess the pressure can't escape and it blows through the gasket eventually. It was right on the exhaust side on the back two cylinders - got to be the hottest part of the head?

That's my guess anyway!

Will

 

[LTD]

Think of it in another way:

Take a small compartment (the little cooling passage). Block it off, fill it with water, heat it up to boiling point - keep heating. I guess the pressure can't escape and it blows through the gasket eventually. It was right on the exhaust side on the back two cylinders - got to be the hottest part of the head?

That's my guess anyway!

Will

Agreed - but at day 1 there should be no problem with the escape.

 

[Will]

Another possibility I guess would be that the old water pump and thermostat, replaced about five years ago, was leaking for a while. During which time it was regularly topped up. Either with tap water or even bottled water (worse!).

Hence the furring up of the head. Perhaps if they'd known or caught it early, a coolant system flush (descaler) would have helped?

 

[Barbanasos]

How s the condition of the bore on the cylinders were the water breached? If it was over a prolonged period it could have caused some damage.

 

[Will]

How s the condition of the bore on the cylinders were the water breached? If it was over a prolonged period it could have caused some damage.

I had a quick look at that when the head came off - it seemed okay, you can see the original honing marks and there was no visible wear lip. The engine didn't appear to smoke at all either - so I'm hoping it'll be fine.

I'm going to pop outside later on, tidy up a few things, clean the engine bay and flush the heater matrix and a few other things - I'll check in more detail later. But you are right - I've seen a failed HG on an old DOHC Ford some years ago that has caused damage to one of the cylinders.

Cheers,

Will

 

[grober]

Anecdotal evidence I heard from an old MB tech experienced on these engines, was to the effect the original factory gaskets commonly failed towards the rear of the engine--- cylinder 3 or 4 . His explanation was that these were the cylinders that ran hotter than the ones closer to the front of the car due to air flow . But I guess these might also be the cylinders furthest from the water pump circulation-- hence the greater degree of furring up reduced flow?

 

[Will]

Some good points there Grober. I also thought it relevant that it were the back two.

The furring/sludge though had to have come from somewhere - I feel that proper coolant made up with soft/distilled water would not have been so likely to have caused this.

I guess I could put too much thought into it, but I do like to know why things happen like they do. I'm thinking that the furring has come from hard water, and as you say - being at the back, the hottest two cylinders also furthest from the pump have suffered because of this.

I never liked the idea of cooling system flushing products, but perhaps they could have helped prevent this blockage if the previous owner had been aware of how mucky the coolant system was.

Will