Cooling system problem

I have an 89 Ford Aerostar with a 3.0 engine. The cooling system is giving me all kinds of headaches. It overheated, I think because of a thermostat gasket. At least that's where I found the stream of steam coming from. After replacing the gasket I now have a problem of running out of coolant. Right now I have completely removed the thermostat and running straight water until I can figure out what's causing the thing to keep overheating.

With the engine cold, I fill the radiator and put the radiator cap back on. I then drive the van three or four times, less than 10 miles each time, allowing it to cool down between each time. As expected, with the thermostat out, it stays very low on the temp gauge. The third or fourth time I drive it, the gauge will start to rise and quickly goes to 75% or higher up to 95% before I get back home and turn it off. When I go to fill the radiator again, it takes between 3/4 and 1-1/4 gallons.

I see no leaks anywhere, the oil system is not contaminated with water, and I don't see any steam clouds following me. I do seem to have a miss in the engine that wasn't there before so I replaced the spark plugs, cap/rotor/plug wires, which I needed to do anyway, and found a fouled plug in cylinder #6. This, however, did not fix the miss. Also, it seems like the miss is worse when the engine is "warmed-up" and at an idle.

I'm thinking it's a head gasket but could this be a water pump problem? I think my coolant recovery system is screwed up, too. I'm waiting on paycheck before I can do anything but if anyone has some thoughts I'd really appreciate hearing them.

TIA, BobW

Reply to
BobW
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Ive heard of similar before. Cant remember the exact circumstances.

As you already surmised, it could be one of several things, worst perhaps being head gasket or cracked engine block or head.

Water pumps can also leak water as you have suggested.

Have you been able to take a look in the area of the Welch plugs (freeze plugs) to see if these may be rotten?

Reply to
HLS

If it has already run hot, it may have been hot enough to damage a head gasket. If that has happened, it will build excess pressure in the cooling system and expel coolant. You can get test strips a most parts stores to test for combustion gas in the coolant. Your comments about the misfire may also indicative of a head gasket problem. It is not likely a water pump based on your description of other symptoms. A water pump problem may also exist which precipitated the whole sequence of events. For this reason, you should count on replacing the water pump and the thermostat as part of the repairs. In addition to the coolant test, I would advise a complete diagnostic scan for any fault codes. A well equipped shop will have a scanner that can run a cylinder balance test to identify any weak or misfiring cylinders. A compression test would also be helpful. If the engine is high mileage or has really run hot, you may also find a cylinder leakdown test helpful since piston, ring and cylinder damage may be present. Once you get a good idea of exactly what the damage is and the current condition of the engine, you may want to consider a complete rebuild or a replacement engine of some sort. Those engines are fairly common in salvage yards for a cheap replacement. They are also known to be good exceptionally high miles with proper maintenance. Immunity from overheating damage is better than many other engines including the 3.8L which is very unforgiving.

Lugnut

Reply to
lugnut

The freeze plugs all look okay. After replacing the thermostat gasket I've not been able to see any water/steam leaks so I'm pretty sure the water loss is either through the exhaust or back out the radiator relief cap. Thanks for the thought, though.

Reply to
BobW

Engine replacement is not a possibility. If that has to be done then the van's going to the scrap heap. A full engine rebuild would be nice but also not a possibility at this time. I suppose I could start with the removal of the water pump for an inspection. A gasket wouldn't be much if there's nothing wrong with it. Back, shortly after I bought the van I had the water pump go bad. When I pulled it off, the "blades" of the impeller had been TOTALLY warn away so instead of a lopsided "L" shape, they were "I" shape and just "slicing" the water instead of moving it. It was like they had been eaten away by acid or sand-blasted down to nothing. Never saw that before and I'm wondering if something like that has happened again.

Thanks for your thoughts. I just don't want to start digging into it and have one of those $2.50 "DANG! Why didn't I think of that!" kind of moments.

Reply to
BobW

While running, the temp is rising fast exactly when the level in the radiator is low. While running, the engine is full if the radiator doesn't go empty.

Reply to
Matt

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