couple of cooling questions for a 88

[dirtlord420]

1. i don't understand this cooling system. i tried flushing it but couldnt figure out how the coolant is getting to the radiator.

2. how do you burp the system?

3. my problem is its over heating. the idot light isnt working. the coolant bottle was full for some reason. i bought the truck from a family member. i even drove it a few times before never had this problem. am pretty sure the eletric fan isnt working either. the clutch fan is good. am also replacing the t-stat. rewiring the eletric fan to a switch. what eles should i check?

4. my uncle ran 20w 40 oil in it. then when he drove it to my place he said he put some 5w 40 in it. b/c it has a really bad valve cover gasket leak. then i put some 10w 40 in it then it over heat. could this be part of the problem?

[mvusse]

Valve cover oil leak is quite common, and often caused by a plugged CCV orifice. This will also cause the vent tube to puke oil onto the air filter.

 

Most common cause of overheating is low coolant (but you said overflow was full) followed by a plugged up radiator.

 

Other causes can be fans, water pump, thermostat, air in the system etc.

[BLHTAZ]

Your overheating problem is air in the system because of that idiotic closed cooling system.

 

The best way to remove air from the system is to park the truck with the front end pointed down hill. Locate the temp sensor at the left rear corner of the head (points straight up under the MAP sensor on the firewall) and remove the sensor to allow the air to escape and then screw it back in. If you have nothing but flat land...just jack the rear up as far as you can and do it that way. The idea is to get the air bubbles to move to the rear of the head and go out the sensor hole when removed.

 

There are options for converting to an open style cooling system and several different threads on this site about it if you do a little searching. ;)

[maddzz1]

If the idiot light isnt working it could be the temp control sensor is bad or a bad bulb. You colud always get a new cluster w/ gauges.

[Geonovast]

If the idiot light isnt working it could be the temp control sensor is bad or a bad bulb. You colud always get a new cluster w/ gauges.

 

The gauge and light use different sensors. With swapping in a full cluster, the oil pressure sender and temp sender would have to be replaced.

[maddzz1]

If the idiot light isnt working it could be the temp control sensor is bad or a bad bulb. You colud always get a new cluster w/ gauges.

 

The gauge and light use different sensors. With swapping in a full cluster, the oil pressure sender and temp sender would have to be replaced.

I guess i should have added that part. My bad. :oops:

[Eagle]

Someone mentioned "overflow" bottle. On an '88 4.0L that is NOT an overflow bottle. It is a pressurized surge bottle. It should be filled halfway when colt. Whatever you do, DO NOT remove that cap when the system is hot. Repeat -- it is NOT an overflow bottle, that cap is your pressure cap and if you open it when the system is hot and pressurized you WILL get scalded.

 

The best way to burp the system takes a few minutes. With the engine cooled down, remove the cap from the bottle and fill it to half full. Leave the cap off, or just start it on but leave it loose. Start the engine and let it idle for a few minutes. It speeds things up to partially block the radiator with a sheet of cardboard.

 

As soon as it gets hot enough that you get boiling in the bottle, shut off the engine. Stand by with a bottle of coolant mix in your hand. As the system cools down, it will suddenly start to suck the coolant down out of the bottle. Pour more in as it sucks down, but don't fill it more than half full.

 

When it stops sucking down, fill to the halfway mark, start the engine, and repeat. It may take three or four cycles to get most of the air out. After that you're good to drive it, just check the coolant level every morning and fill as necessary for a day or three until it's fully stabilized.

[deziped]

Preceding comment is correct. I just went that route 2 days ago after install of new radiator. I filled it as much as possible through heater hose & then filled bottle 1/2 to 3/4 full then :brows: I just warmed vehicle up[to normal (210) tempaerature then shut it off & went & took a nap. Couiple hours later I had to run to store so I add more 50/50 to bottle. Checked it when I got back home & yup it had been sucked down while I was in the store. When it cooled down I added some more & was ready for the next warm up. Anyway it's now fullup & belched & workin fine. It may not be as quick as some other methods, but it's easier & less messy. :brows:

[Comanchero87]

Reviving this old post. Attempting this process. Should there be a good flow through the bottle return line into the bottle with cap off on its way to operating temp? I can't get the bottle to boil. Ive got it up to operating temp but it just over flowed from the bottle once I turned it off. I still hear a dibbling sound like the water is running back into the engine no sucking sound except the first time when the bottle ejected all is coolant.

[carnuck]

Air is trapped and the stat hasn't opened yet. This is why I switched to a '91 up rad. It has a cap you can fill!

[Shane]

I had the same issue with over heating. One thing is make sure that you have the right temp sending unit. The one for the light ha a slot in the top and the one for the gauges has no slot. Analternative to the coolant bottle and if you are on a budget and can't convert to an open system, check out macsradiator.com the have some aluminum surge tanks.

 

http://www.macsradiatorshop.com/surge-o ... tanks.html

 

They are at the bottom of the first page.