Pressure in my cooling system

[cfilm1]

In the city my 74 Bronco with a 93 5.0 motor and crossflow radiator runs cool. As soon as I get on the highway the systems burps out of my Be Cool catch can and thus progressively as the water escapes the system the motor begins to run hotter. The mechanic that works on my cars says the block might be warped. We just had the heads resurfaced and new head gaskets installed and he thinks compression is entering water jackets there. I see no water in the exhaust though. My brother wants me to change the water pump thinking it might be cavitation causing pressure to build up. Any ideas or knowledge on the subject would be greatly appreciated. This is the third time this month I've had to ride home in a tow truck and AAA is about to drop me. I stink like antifreeze please help.

[megaladon6]

i agree with changing the pump. it probably isn't pushing enough volume causing the water to stay in the block too long and overheat.

[JEFFTATE]

Try the water pump , but I don't think it is going to fix all your woes ..
It sounds like you've got cylinder pressure and/or heat entering your cooling system.

I'd start by pressure testing the cooling system first and look for the leak...

You can borrow a cooling system pressure tester at AutoZone.
Pump the system up and look for the leak..

[megaladon6]

autozone may also have a gas tester. basically you put it in the rad opening and put fluid in it. run the engine and if the fluid turns color, you have exhaust gasses in the coolant.

[TT302Z28]

I agree with megalaon6, I bought my tester at Napa just in case you have one near you.

[mrn2obelvedere]

I'm thinking a head gasket problem.

[MonzaRacer]

OK first of all does it still a 93 water pump and does it have all of the original 93 brackets and pulleys or did you install all the old stuff.
What you might have is a reverse rotation water pump causing issues or a bad separator plate.
Generally if it has a head gasket issue it will over heat sitting also.
VERY rarely do they only over heat at cruise.
This generally means an air flow or coolant flow issue
Also if the system is full as it warms it may bring up the level in the tank then go down,especially if it has a large radiator.
also double check your fan direction if you have one that is reverse rotation it will work sitting still but not at speed.
Basically the "cutting" edge should towards the radiator. IE air blowing towards the engine.
Also a thermostatic clutch fan really helps and a good solid shroud.
Also get the cap tested as this can cause issue,,, the thermostat temp, if in the 190 range can cause issues if you dont have a good pressure cap, also make sure your lower hose isnt sucking shut, you need a lower hose with the spring inside.
Good luck.

[cfilm1]

Thanks for the ideas. I know that it does have a v belt style water pump on the front because I have the old one from the motors serpentine days and it has a passenger side port which is specific to the older ford motors. I have no idea if the pump is good though. I didn't rebuild this motor I just cleaned it up. It is shrouded and the fan is spinning the right direction so I think I will try testing for fuel in the system then go get it pressure tested and then I guess I'll know if its head gasket issues. I may also try a different cap. I have a 16lb cap on there now. I am running a much smaller overflow bottle than the original but I can't imagine the original system dumping half its contents into the original overflow bottle. That would have shown up before the restoration. I thin i'll head down to Napa.

[Jim Nilsen]

Thanks for the ideas. I know that it does have a v belt style water pump on the front because I have the old one from the motors serpentine days and it has a passenger side port which is specific to the older ford motors. I have no idea if the pump is good though. I didn't rebuild this motor I just cleaned it up. It is shrouded and the fan is spinning the right direction so I think I will try testing for fuel in the system then go get it pressure tested and then I guess I'll know if its head gasket issues. I may also try a different cap. I have a 16lb cap on there now. I am running a much smaller overflow bottle than the original but I can't imagine the original system dumping half its contents into the original overflow bottle. That would have shown up before the restoration. I thin i'll head down to Napa.

Sometimes it is just the steam that goes into the overflow that comes out, if the overflow tank isn't comlpetely full and the hose coming out the top of it is truly at the top it was just the steam that went through.

It might just be a bad cap as well as too low of pressure. I use an 18lb cap and may go to a 21lb because the temps can be brutal at the track and the more pressure usually the more flow you can get sometimes.Plus it keeps it all in at higher temps.

[MonzaRacer]

OK 93 engine probably had a reverse rotation water pump if the old serpentine WP pulley is smooth your water pump is going in wrong direction, you need different pulley bracket set up or different pump.

[dirkly]

I remember doing a set of head gaskets or intake gaskets on 5L once and got the gaskets backwards ( they will bolt right up and look normal but there are some water passages that will get blocked if on the wrong sides) It would idle and run normally until the revs were brought up, then it would start puking. Sorry for being a bit vague but this was years ago!