...run my truck with the radiator cap? I've been trying to figure out this heat problem that I have and the only things I can figure is 1) my heater core is partially blocked, or 2) I have air in the cooling system. So the way that I have been told to bleed is system is to run it with the cap off. So I did this and not only did bubbles seem to come out but the dern water like started almost shootng out of the radiator! It didn't get super hot but could that just because of heat? Right when I shut if off it shot out a last burst of coolant..nice mess. So I cleaned it up, added coolant back in and it seems to be doing okay? Anybody got a clue what the heck is going on here?

 

If there is air in the system, when the tstat opens it may burp over, it shouldnt overheat just because the cap is off...run it with the heat on and the cap off until it is at operating temp for 10 minutes...heres where its tricky and i swear by this...

-have someone (unless you can multitask) hold the RPM at 2500
-top off the radiator
-install the radiator cap
-release the throttle...you will now have no air and you will have cooling system pressure immediately

 

Okay i'll have to try this and get some help..tonight I was out there alone. But so running with the cap off is okay right? I have don't it before to get the level right after a flush and I've def. Never experienced what it did this time.

 

if it burps out its because there was air...if the temp gauge reads high and it is like a volcano, thats ungood

 

Lo well it was doing quite a bit of burping but the gauge def. Did not read super high. I don't think it got much past 175.

 

the center of the gauge is approximately 200-210 degrees just for reference

 

Ya I was just going off my Scan gauge as it has a digital reading...hopefully its accurate hahah.

 

run the heat too with the fan on and allowing coolant to circulate through the heater core will allow air to escape

 

Ya that's what I was going man..I wish I could explain better what it was doing it would like go down in he radiator then come rushing back out. I appreciate your help man..I'm gonna try some more today.

 

I am dealing with an issue similar to this. We had the freeze plugs blow out on us during the summer (I know right?!). Our cousin replaced the freeze plugs and put a new radiator in. We got it back and the temp gauge is going up and down from the N in normal to the L and back again. It never goes past the L.

I replaced the thermostat, with the assumption it was going bad and was opening late and closing early. It did not work

I replaced the fan blades. In-between every blade the plastic was cracked. My thought was if the blades made the clutch off center it might not engage correctly and cause it to not get the air needed. It did not work.

I replaced the water pump. At this point I could hear water trickling through heater core area and assumed the pump was going bad and was not pushing the amount of water needed. It did not work.

Last night I was driving home and the temp gauge spiked to "/H" and did not return down with in 3-4 seconds. I cut the engine off and when I did, I heard GULPING sounds from the heater core.

I replaced the heater core this morning. I do not hear the trickling or the gulping anymore but it still goes up to L but not "/H". It did not work.

I only have the fan clutch, overflow hose, and overflow tank left to replace. **aside from the sensors themselves**

Notes on truck:
It never does this at idle.
There is no specific speed that it does it more or less at.
Often times after this happened I open the hood to find the connection from the overflow hose to the overflow tank has expelled coolant. *Not a lot but some - tank is still 1/2 full*
When I open the radiator cap after it has cooled (warm not cold) it releases pressure and I can hear it blowing air/air bubbles into the over flow tank.
After it does this the radiator cap is cool to the touch but the radiator is hot.
When I open the radiator after this has happened and the engine is cool I need to add 1/4 to 1/2 gallon of coolant.


Any thoughts?

 

Matt, you dont have a blown head gasket do you?

 

It may be still a problem :/. I had a slight leak outwards on the passenger side cylinder head and I used a bottle of stuff some good mechanic friends of mine recommended...like 65 dollars a bottle stuff. It def. Got rid of the leak but it could still be occuring just not as bad. Thankfully its not going inwards..my oil is always clean.

 

Is there a name to this stuff?

 

Ya I was trying to think of it but ill have to check w/ him.

 

Well I have to concede I think it is the cylinder heads and/or gasket.

Symptoms why I think such (please correct me if wrong)

1. The truck has started to burn "something". I thought it was oil but did not smell like it. Once warm (generally) it stops.
2. I cleaned the throttle body recently and noticed oil in the plenum.
3. I did the radiator test and it kept bubbling out and did not stop 45 secs to 1 minute of coolant pushing out of the radiator and bubbles coming up.
4. On certain days at certain times you can see the puffs from the exhaust as coming from one cylinder as it is timed puffing.
5. My issue with the overflow being bubbles is this. I think the truck is consuming the coolant and creating a "negative pressure" (vacuum) on the system and then when I open the radiator cap it is sucking the fluid from the overflow back into the system (the bubbling was the amazing rate at which it was pulling it back into the system). This vacuum / void creates the hot spots that keep the truck temperature up and down.
6. Today when I went to leave for work the truck did not want to turn over (like starter was stuck). Not from dead battery, but it sounds more like hydro lock. It tried it 4-5 times and then it started up no problems.

If this is the case how much for new heads and can anyone point me to a location I can purchase them at? All I see is Edelbrock stuff for V8's.