Coolant Foaming in Perkins 4108

[wanderlustv]

Hi All,

Have a perkins 4108 that is loosing coolant at a rate of about 1/3 of the header tank per hour running time.
Thinking it may have been going out with the raw water i cleaned out the heat exchanger but it looked okay. Then put it all back together and ran the engine for an hour.
For the final ten mins of run time i took it up to max rpm about 3000 and notice coolant foaming out of the header tank vent. It did not do this at lower rpm just at full noise.

Am now suspecting a blown head gasket but has anyone else have ideas or experienced a similar problem?

[SimonV]

I agree blown head gasket.

[Jesse]

I think your suspicion is right on the money.

[olaf hart]

Or a cracked head

[Seahunter]

Was the coolant foamy before you cleaned your heat exchanger?

[wanderlustv]

No before i cleaned the HX it was just loosing coolant, the foaming only happens at high RPM which I am now thinking may be a pin head size hole in one of the HX tubes letting in salt water which would account for the foaming.
Im trying to exhaust all other options before pulling the head.

[Seahunter]

I have my doubts that it's the head gasket. If the coolant leak source is only showing up in the exhaust without traces anywhere else I would find the tube stack suspect which was acerbated by cleaning. There are significant symptoms of head gasket failure in Perkins. Milky oil and overheating are at the top of the list. If there's a problem with the head gasket, it WILL turn milky regardless of which journal has been breached; it just takes longer for the water to get to the oil, but it will (less than one week). Check your shop manual, it gives good references. The fact that the coolant is foamy indicates that the fresh is mixing with the raw water, not steam. You should also make sure you put the end cover boots, and "O" rings back on properly and that they're not kinked or damaged. Make sure to pressure test the system once you've replaced the stack.

[DeepFrz]

Probably a good idea to pressure test your heat exchanger.