E30 Zone

willnz wrote:

Brianmoooore wrote:but wouldn't it be a good idea to do some diagnostics on your existing head first, to establish whether or not there is actually something wrong with it?

My thoughts exactly!

willnz wrote:Before you strip anything, get the cooling system pressure tested, making sure the engine is at operating temperature. Remove the cam/rocker cover before doing this test. While the test is underway, look for water weeping up from under the camshaft, particularly towards the rear of the head. This is one spot where the head is inclined to crack if overheated.

If you confirm a pressure leak in the cooling system, but do not see any trace of water escaping under the camshaft, you should then investigate whether it has blown the head gasket between the oil and the cooling galleries. (This because you have found sludge on the dipstick, suggesting water is mixing with the oil).


Hi Man, thank you for your reply and help.

I will check and see what is going on!! When the head gasket was replaced I bought a set of Victor Reinz head set which I belive is a very good brand???

No the engine never overheated!!

I will check and inform asap
I would also examine the spark plugs for evidence of water leaking into the combustion chamber- normally this will make the porcelain on the spark plug very white. If this is evident, it could point to cracking through to the inlet/exhaust port and/or head gasket failure.

If you had overheated the engine recently (I assume you have not or you would have mentioned it), you could reasonably expect a cracked head. These heads do not normally crack out of the blue. I think you have a good chance that the head gasket has failed, not the head. Check before just buying a new head.

If it is a head gasket failure, make sure you get the head/block surfaces checked for straightness and use a decent head gasket, not some of the cheap asian sh*t that is floating around..!!

Brianmoooore wrote:I see nothing in the OP that convinces me that there is anything serious wrong with the engine at all. The two symptoms mentioned are a small coolant loss and a few small spots of mayonnaise on the dipstick.

Coolant loss: In my experience, a M20 E30 will not maintain the level in the bottle at the correct point. It will blow out coolant until it is around 10mm - 15mm below the seam on the bottle, and then nor drop any further.
I once had a M20 as a daily driver that would very slowly consume coolant. It took two years to discover a very intermittent drip from the water pump, that only occurred when the engine was running, and only when it felt like it.
There can be a tiny hole in the radiator matrix that evaporates almost instantly, or a pin hole in a hose leaking a jet so fine that it's impossible to find until you accidentally put your hand in the way.

Mayonnaise: The spots on the dipstick were picked up on the stick as it was withdrawn. If it was the general condition of the oil, then the whole of the dipstick would have been covered in it, and the level probably high.
The combustion of petrol produces vast quantities of water vapour, some of which will end up in the oil as part of the small amount gasses that blow by the pistons. The majority of this is boiled off by the hot oil and extracted by the crankcase vent. system, but some will find its way into cool nooks and crannies, such as the dipstick tube or oil filler cap, and form small quantities of mayonnaise.