my 1989 740 turbo has suffered sudden full coolant loss and over heat.
now it will not hold coolant at all. it just leaks out as fast as i put it in.
may be blown head gasket or "freeze/Soft" plug cant tell need help bad.

A blown head gasket would not typically allow coolant to pour out as fast as you pour it in, it would seep out of the joint between head and block very slowly. Head gasket does not usually fail unless the engine was allowed to overheat to the extreme due to coolant loss or some other reason. The head gsaket is then a secondary problem caused by the primary problem. Freeze plug failure is very rare unless the engine froze up with no antifreeze, but I am sure you did not allow that to happen.

A sudden and very high volume leak is more likely a blown hose but that should be easy to spot. you must carefully observe exactly where the coolant is coming out to correctly diagnose the problem, no guessing allowed.
--
David Hunter

Fingers gave you good advice about things to look at--you do need to get under the car and look around some. If it is coming from the front of the engine then I would think about two things:

Turbo oil cooler coolant hose became oil-soaked and failed.

Water pump seized due to a bearing failure around the pump shaft and the pump impeller smashed the pump casing resulting in the leak.

Hope this helps! My sense is that it is something other than a head gasket, so I hope so!

Mike

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Mike Brown Greenville, NC 1996 965 113K 1994 940 135K 1986 244 137K

first things first. Remove the engine shield (the plastic shield under the engine). Second, get a buddy to pour water in her while you get under and try and find out there the water is coming from. It's far more likely that this is a few dollar fix that a few hundred. My guess in descending order of likelyness is:
1 hose, lower
2 radiator
3 water pump

Did I forget to mention that you should switch to water for this diagnostic? You can go ahead and start this vehicle( if it ain't leaking of course)as it will take a minute of steady water pumping to warm up- much less overheat.

Good luck,

the leak is located some where behind timing cover

Abel,

If your leak is directly behind the top part of the pulley in the picture below (center of the picture), then you've probably torn the thick rubber seal that sits between the top of the water pump and the protrusion in the head.






If this is the case you technically can fix it by replacing only the seals and the water-pump gasket, but it would be advisable to replace the pump as well at the same time. See FAQ link for more info.

Good time to also check and replace your timing belt !

Noel

If it coming out that fast - you may have blown a head gasket really good. I would think that it is time for a shop.

Had this happen on my 745t - but it was not coming out that bad. Stopleak worked for a spell - but I eventually had to take the head off, get it resurfaced and straightened - and put a new gasket on.

Be blessed.
--
'89 764 (110K), '94 940T (180K) , '92 745T (totaled 2-10-05 RIP)

likely a water pump. volvo's are famous for blowing up water pumps. I blew through two in my '79.

Hello,
My 1986 740 water pump went in exactly the same way. The cooling water just poured out from the pump area and virtually emptied it out as soon as I had re filled it. I drove it about 3 miles to the mechanic and kept stopping and pouring more water in and he fitted a new water pump as the old one had totally gone. It was a cheap repair about £75.00 UK pounds.
I learnt a very good lesson. Always replace the water pump when you buy a used volvo if you dont know if the pump was replaced recently. It could cost you a headgasket if you dont realize there is no coolant and it gets way too hot.
The same thing happened to my Dads 1985 240GL. No harm done, he realized before it was too late.
I would now do my own waterpump replacement as I fixed my Dads 240 for him and found it quite a straightforward job with a repair manual.

Here is a rough quide.

Undo the two screws on top of the radiator fan shroud and remove shroud. Pull it up.
undo the 4 nuts on the back of the fan and pull fan towards radiator.
slacken the pulley belts by using the tensioner screws and remove belts.
pull off the pulley on the water pump shaft.
Remove upper timing belt cover, 2 bolts. screw on top at rear of cover. (all visible)
remove bottom radiator hose from pump.
Undu the pump bolts and remove pump. may need to give the pump a gentle tap to free it.
Fit the upper rubber seal on the top of the new pump. Fits into hole at top of pump.
Fit the gasket onto the back of the pump. I used RTV sealant on the fibre gasket on both faces to make it totally leak free.
I then fitted the o ring onto the heater pipe at the side of the pump and then cleaned the mating surfaces of the engine and head and then offered the new pump into position making sure the o ring on the pipe at the back of the pump makes a good seal and the o ring dosent slide along the pipe.
Next tighten the pump nuts up loosely and then use a bar or long screwdriver to lever the pump up to compress the rubber seal on top of the pump, and at the same time tighten the nuts up.
Continue assembly in the reverse order and then fill the cooling system with new antifreeze/water 50/50. Run the engine and continue filling until all air is out and the heater is blowing hot air. Check level later on and top up if neccesary.
Good luck Kyle 123.