Block Drain On 1986 951

[Lawrence Coppari]

I am getting ready to change my antifreeze. Does my car, 1986 944T, have a block drain plug? And if it has one, where is it located? Thanks.

[1.2gees]

Yes it does, I don't remember the exact location, but it does have a drain plug on the block. It's close to the exaust manifold, near where the control arm bolts on to the chasis, (the rear of the control arm, away from the balljoint, and the aluminum subframe). It's on the passanger side (of a US car) of the block. The bolt is about the size of the drain plug for the oil pan.

I can look further if you can't find it...

BTW, you don't HAVE to use the plug to drain all the coolant, if you don't, make sure you add the water from an upper hose, directly into the engine block, or your thermostat won't open...
Ahmet

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It's all the driver...

[Lawrence Coppari]

Ahmet, thanks for the advice. I have a question about what you said.

BTW, you don't HAVE to use the plug to drain all the coolant, if you don't, make sure you add the water from an upper hose, directly into the engine block, or your thermostat won't open...

Do you mean that if I do use the plug, there there is no problem with the thermostat sensing the temperature and opening when it should? I know where the air bleed is located. If I open that, will that be sufficient?

Thanks again.

[1.2gees]

Actually, I think the ultimate way to flush the system would be to take out the coolant drain plug from the engine, disconnect a lower hose from the radiator, (or take the radiator out altogether), and disconnect a lower, and upper hose from the engine.

Than put water through both the engine, and the radiator from the upper openning(s), and flush until you see clear water coming out at the bottom. To properly flush ALL the water that's in the engine, drain plug must come out, but I don't think it's so important.

Now, even if you do take the plug out, you should add water directly to the block, from an upper openning, and then worry about the overflow tank/radiator. If you don't put water in the engine block, your thermostat will NOT open. You can add water through the upper bleed plug, again directly into the engine block.

The reason for this is, if there's no coolant in the engine block, regarless of how hot it gets, the thermostat will not open, and thus the pump will only push some hot air through the engine. I cannot believe the service manuals don't mention this...

Does this help?

Good luck, if you have any questions, feel free to ask, and no problem.
Ahmet

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It's all the driver...

[1.2gees]

Reading over my last reply, it's NOT sufficient to take out the bleed plug, you MUST add water either through the bleed plug (high on the engine block, and fill until the coolant is level with the highest openning on the block, since the head is what get's the hottest, and water will not circulate until thermostat opens, IF there's any air) and keep the plug open for a good while, adding coolant when/if level goes down.

NEVER drain coolant out when the car's hot, or even warm, the factory manuals suggest at least 6 hours since last cranking, or you might warp the engine block (very easily). Keep an eye on the temp gauge, when you start the car, and let it warm up, if it goes ANY higher than normal, shut it off, and wait before you drain the coolant (if you want to drain the coolant) until engine is cold again.

Remember, an engine that gets to operating temp with no/low coolant isn't likely to cause damage, but draining the coolant (whatever the level), or adding cold coolant to a warm engine will most certainly damage it...

I hope this wasn't overly complicated, just wanted to make sure you know of all the warnings I can think of.
Ahmet

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It's all the driver...