Changed coolant, overheat problems now.

[beatshack]

This is a very strange problem, and couldn't really find a more appropriate forum to post in, so here goes:

About a month ago my thermostat failed open, so I've been driving for a while with no thermostat. No problems, just takes forever to warm up. I drained all the coolant, put in a new thermostat (I installed it correctly with the bleeder towards the firewall). Filled it via rad cap back up with new 50/50 coolant to the top, started the car, let it reach operating temp, thermostat opened, upper rad hose got hot etc etc. Let it cool off, added more coolant. Drove it around that day, no problems.

Today in the morning I opened the rad cap and noticed there was no coolant in the upper hose, so I filled it to the top again, closed it. Overflow bottle at full (i know thats a little much for the car being cold, but whatever). Drove it around today, until suddenly I noticed my coolant temp shoot up to 104 degrees C while I was at a stop light, and the temp was climbing to 110 C, so I parked it, let it idle for a bit and noticed the rad fans were not coming on. The upper rad hose was hot, so I assume the thermostat IS opening fine.

Now before you just assume the culprit is engine temp switch, get this: After it cooled down I started it up and drove it home, and it was usually staying at an alright temp while I was cruising down the freeway, but I had NO HEAT in the car. Then boom all of a sudden I'd be getting heat again, and the water temp would drop to normal cruising temp. Then I'd get cold air again coming through the vents, and the water temp would jump up by 10 degrees C. This went on and on, until the air temp was FREEZING and the water temp started to hit high 90's.


This is really confusing to me. My guess is that there is either a large air pocket, or some debris clogging the heater core lines.. but that still doesn't explain the fans not coming on does it?

HELP!! Thanks in advance.

 

[beatshack]

OH BTW, the thermostat I put in opens at 71*C rather than the stock 88*C. I like to run a cooler thermostat in the summer.

 

[DSM MAN]

Wow that is pretty odd. I would say burp the system and see if there is some air in there. But definetely not right. Goodluck .

 

[beatshack]

Update: This is another really weird thing. So far since I've installed the new thermostat and changed the coolant, every morning when open the rad cap there is NO coolant in the upper hose at all. And the overflow bottle is really high, way above the full line. I have been pumping out enough coolant from the overflow so its between full and add, and after driving it overflows coolant. I am starting to fear that my HG might be gone. I don't get white smoke on start up though, and the coolant is clean, no oil. Oil is also clean.

I will try burping the system with the rap cap off, squeeze all the hoses when it hits operating temp.

 

[lngbrdr]

Update: This is another really weird thing. So far since I've installed the new thermostat and changed the coolant, every morning when open the rad cap there is NO coolant in the upper hose at all. And the overflow bottle is really high, way above the full line. I have been pumping out enough coolant from the overflow so its between full and add, and after driving it overflows coolant. I am starting to fear that my HG might be gone. I don't get white smoke on start up though, and the coolant is clean, no oil. Oil is also clean.

I will try burping the system with the rap cap off, squeeze all the hoses when it hits operating temp.

Let me know if you figure it I'm having the exact same problem minus the air conditioning thing. Only thing is I am burning oil too so I am fearing a headgasket but I still have good enough compression.

 

[dsmkid4g63t]

sounds like you have air in the system, try and burp out the system, also i would try and pressure test the system and cap...check for leaks, a bad radiator cap will also cause an overheating problem...

 

[beatshack]

^^ I believe you are bang on in both cases. The reason I was not getting any heat through the vents was low coolant... very low! I found out there was a small hole in the hose that goes from the thermostat housing to the overflow bottle. Which is just as bad as having a crappy rad cap. So what was happening was the system was not able to suck any coolant from the overflow bottle; instead it just kept overflowing until I basically ran my coolant very low each time I drove. I believe the thermostat is fine. And since the thermosensor switch that turns on my fans has to have coolant touching it to work, the fans weren't turning simply due to lack of coolant!!

So today I drove it with a/c on full blast, both a/c and rad fans going full blast, and managed to get to a place to get a new rad cap and new hose. Hopefully this is will cure the issue. I'm pretty sure it will.

 

[beatshack]

Update: I replaced the hose and rad cap, and no more overheating. The coolant system is now pressurizing normally and is sucking up overflow instead of dumping it to the ground.