I have a tool that pulls a vacuum on it, and lest me fill the cooling system with no air bubbles trapped in it. It's a good time saver, but for whatever reason, it sits at full vac for about a minute, and then for the next minute it slowly bleeds off. I haven't put coolant in it yet because I don't want to fill it and find out it has to come back apart, or if something S isn't seal and possibly damage the motor if coolant is getting into the cylinders or oil.

Im going to rent a pressure tester and see if it holds pressure, but what's the best way to go about finding a leak like this?

 

Fill it water, or coolant, start it up, let it warm up, and build pressure. See where the drips are.

 

Idk just pissed at the situation. I've out too much money into this truck and nd I still can't get it to run right and not run hot. I need it by Sunday, gotta tow my buddy's truck from the farm to his house. But what I mean is I find there are no drips. How am I able to tell if it's internal? What's the likelihood that the head gasket didn't seal? I cleaned the block and everything. The only thing I wasn't able to get off the block were the stains from the old gasket. It was smooth and clean, but do the stain from the old gaskets matter?

 

Stains don't matter, so long as the surface is clean, and smooth.

Fill the cooling system, and burp it good. (leave the cap off.....) Retest for combustion products in the coolant. Also, watch for bubbles when the engine is idling, and the system is full. Let it sit and cool for 30 minutes or so, and check the oil. If there is no evidence of coolant in the oil...... use a pressure tester to pressurize the system, and see what happens. Bear in mind though, that everyone and their cousin uses the rental tools from the parts store.... and they don't always take good care of them.... so, the tester may not seal well at the radiator, and your pressure will bleed off there. (some soapy water sprayed around the radiator/tester will show that though.)

Also, don't forget to check the passenger side floor.... overpressurizing the cooling system may have compromised the heater core.......

 

Well I get the pressure tester and found out that the freeze plug on the block underneath the power steering pump. I got a expandable plug in for now cause I couldn't get a normal one to seal. I then pulled a vacuum on the cooling system, and it held for 15 minutes, and then I filled it up. Bled it and tried to burp it, being that I drained the block, I was able to get 4 gallons in, probably what's left and and what's in the heater core makes up the last of it.

I drove it and let it cool down and then I drove it to school this morning and the upper hose is rock hard just like before. When I had the heads off, I didn't see any signs of a blown head gasket. No sight of it on the old gaskets, and no coolant in the oil nor coolant in the cylinders(or signs there of).

Im at a loss, because now the guage fluctuates even more. Gets hot when you get on it, and then cools down when coasting or idling. What's the possibility of a cracked block? And would I test like that the same with the block tester?

I NEED to tow with it this weekend, so I'm going to double clamp all my hose connections and I think I'll be fine for now. If I lose it on the road I lose it. I just have to have it.

 

Does the motor run well? If so, check the coolant level again at the radiator cap once it cools down. I suspect you still have air in the cooling system. It takes a bit to get all of the air out.

 

I would also get the tester for combustion gases in the coolant......

The system will build pressure as it warms up. But, if it gets rock hard as soon as you start the engine, you have a problem.

 

Been driving on it awhile, no change in the issue. After repacing the heads, what do you thing could be the issue? If it a cracked block? And how would I go about figuring that out?

ive spent way too much money on this ol truck, not worth my time in case the block is cracked. I'm thinking I'm just going to drive it till it dies, which I'm not sure how long that will be.

 

Do the hoses get hard as soon as you start it? The system is supposed to run at 16-18 PSI...... but, that's when fully warm....

 

Yes. Going to do a cmpression test here soon to see if I can't isolate which cylinder if that's where the pressure is coming from.