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Ron Stygar Carl Buckland Dale Beuning Forums Help
From digest.v7.n31 Fri Aug 1 07:17:45 1997 Ok, lets get through the basics of 2002 (all 4 cyl) head gasket etc problems. Lotsa this applies to chain driven 6's (non-rubberband motors) as well. YMMV The oil looks like a Frappe (milkshake to other parts of the country) is not a good thing. This almost always means that the head gasket is blown. It may also indicate a cracked head. Water in the oil never indicates a cracked block. Period. A cylinder head can crack in several common places. It can crack near an exhaust valve seat. Fairly common. This will get you steam shortly (under 1 minute) from startup. The steam will have a slight sweet sticky taste to it if you inhale it. Very similar to the taste of Vanilla Ice Cream that has been allowed to melt partially. And, even though Carbon Monoxide is odorless, colorless and tasteless, it too will leave your tongue feeling like you let some vanilla ice cream melt on it. Back to the cyl head. This type of a crack wil usually seal itself after about 3 minutes. Aluminum expands, seals crack. And results in very little coolant loss. Here we have a cylinder head which in the cold (relaxed state) has an opening, allowing water to creep past and turn to vapor upon hitting hotter exhaust gases. Stay with me. Engine runs on 3 cylinders. A compression test co-mingles two adjacent cylinders. Head gasket is blown across two adjacent cylinders. Car has a bad skip/miss. Take a comression test with only one plug out, normal. Suddenly you take out one or both of the adjacent cylinders spark plug and you hear a hiss and the compression gauge only goes to 60# or so instead of the 140# you were hoping for or had with the other spark plug in place. Of all the cylinder head/block problems this is the one which needs to be fixed soonest. The engine firing across two adjacent cylinders will erode the head to a point that it is junk. Or junque. When you are missing .070" no amount of machining can make up for this. Next nasty situation is the engine is warm, bad head gasket. Water will get past the head gasket in the water galleys. Now you get Co and Co2 in your cooling system. This can be checked real easily. Simply use a Co meter and test the gas coming out of the radiator or cooling tank. There are also a number of test kits using a litmus type test that will detect this. Block test, head test etc. They use a fluid in an evacuation chamber which will indicate a change of color (ph) upon the presence of exhaust gases in the coolant. No matter, blown head gasket. For sure. Next scenario is oil in the water. Ugly black/brown droplets floating in the coolant in the radiator/coolant overflow tank. This is nearly always the symptom of a cracked head o block. Oil gets into the coolant at a point where the oil pressure exceeds coolant pressure. Think about it, and don't bother debating it on the Digest, please. This happens when the cylinder head cracks under a cam journal. Period. At this point oil pressure exceeds water pressure, oil contaminates water. That's it for normal failures. I'm sure that there is someone out there who has had an incredible experience like the head cracking vertically along a galley the head bolt goes in to. Or the twit who screwed up the assembly of an engine. Those war stories and others will appear in a compendium of fiascoes in the Roundel this winter /next spring. I've dealt with the "normal" steam, water,oil fiascoes. And, hey, I don't have all the answers yet either. But I have time on my side. And, I've driven a 1200cc BMW for 600 miles (BMW 1600 less one) Feb 69.. Western NY to Boston with only three pistons, one blew up, was removed, rod removed (actually cut) no # 3 piston in place and made it back here with full oilpressure! And got 21 MPG as well!
Please, no flames. This information is presented only as advisory, don't try
this at home etc. |
