Hi everybody,
I have a '89 325 with a b35 swap from a 1992 e32. I have been having cooling issues with the car ever since I bought it about a year ago and now finally the cooling system has gone to hell. I need some major help because I cannot diagnose the problems it is having.
Here is what happens to the car.
1. I turn on the car, everything seems fine so I start to drive.
2. After the first 2-3 minutes the engine temp rises at an unsettling rate until it is almost at the red zone. Mean while, if I turn on the heater it will not blow hot it will only blow ambient air.
3. The engine will stay at this high temperature, but when I rev the engine at this point to above 4-5k something happens and the engine temp will go back down to a normal running temperature (just below the middle of the gauge).
4. After the engine has returned to a normal running temp the low coolant light comes on, on the check panel so now there is no coolant in the res. tank but the engine is still operating at a normal temp.
5. When I shut off the engine, but then turn it back on (engine is still hot) we start back at #1.
So, this has been going on for a few weeks and finally 2 days ago I came back to my car at a shopping center and i noticed a river of coolant coming from under my car. At this point I say, that enough is enough and I call a towing service to get it towed back to my house.
Now, that brings us up to today. I have pulled out the entire cooling system. That means all the hoses, res. tank, thermostat, thermostat housing, thermostat inlet cover, everything accept the radiator.
Here are some known things:
I know of one leak coming from the return hose to the radiator. It is at the hose clamp on the thermostat housing
I found a hole in the thermostat inlet cover (from calcium build up and corrosion)
I noticed also that there was a lot of calcium build up on the third from front of engine coolant hole on the block (the brass coolant plugs on the intake side of block, sorry I can't remember what they are called). The build up could just be because of the coolant that leaks onto the block or is it possible that coolant is leaking out of the plug?
SO, what I need help with is if anyone can help me solve the cooling problems I am having. Why does it over heat like that then go back to a normal temperature? And is it possible for those brass plugs to leak like that?
Any help is wanted and sorry for the long post.
some pics:

thermostat cover with a hole in it

thermostat seems ok

found some antifreeze build up around temp sender

modified thermostat, I drilled 3 holes in it so there would constantly be fresh coolant flowing into the engine


general layout of hoses

build up around radiator outlet hose into the thermostat cover (where the hole is)

build up around brass block plug
I have a '89 325 with a b35 swap from a 1992 e32. I have been having cooling issues with the car ever since I bought it about a year ago and now finally the cooling system has gone to hell. I need some major help because I cannot diagnose the problems it is having.
Here is what happens to the car.
1. I turn on the car, everything seems fine so I start to drive.
2. After the first 2-3 minutes the engine temp rises at an unsettling rate until it is almost at the red zone. Mean while, if I turn on the heater it will not blow hot it will only blow ambient air.
3. The engine will stay at this high temperature, but when I rev the engine at this point to above 4-5k something happens and the engine temp will go back down to a normal running temperature (just below the middle of the gauge).
4. After the engine has returned to a normal running temp the low coolant light comes on, on the check panel so now there is no coolant in the res. tank but the engine is still operating at a normal temp.
5. When I shut off the engine, but then turn it back on (engine is still hot) we start back at #1.
So, this has been going on for a few weeks and finally 2 days ago I came back to my car at a shopping center and i noticed a river of coolant coming from under my car. At this point I say, that enough is enough and I call a towing service to get it towed back to my house.
Now, that brings us up to today. I have pulled out the entire cooling system. That means all the hoses, res. tank, thermostat, thermostat housing, thermostat inlet cover, everything accept the radiator.
Here are some known things:
I know of one leak coming from the return hose to the radiator. It is at the hose clamp on the thermostat housing
I found a hole in the thermostat inlet cover (from calcium build up and corrosion)
I noticed also that there was a lot of calcium build up on the third from front of engine coolant hole on the block (the brass coolant plugs on the intake side of block, sorry I can't remember what they are called). The build up could just be because of the coolant that leaks onto the block or is it possible that coolant is leaking out of the plug?
SO, what I need help with is if anyone can help me solve the cooling problems I am having. Why does it over heat like that then go back to a normal temperature? And is it possible for those brass plugs to leak like that?
Any help is wanted and sorry for the long post.
some pics:

thermostat cover with a hole in it

thermostat seems ok

found some antifreeze build up around temp sender

modified thermostat, I drilled 3 holes in it so there would constantly be fresh coolant flowing into the engine


general layout of hoses

build up around radiator outlet hose into the thermostat cover (where the hole is)

build up around brass block plug
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