Running hot and at wits end

**johnj4654** · 08-03-2014

05 model GP that temp gauge was fluctuating. It would stay around the halfway mark on the road but would climb at low speed and stops. Unit has new hoses, thermostat, radiator, elbow fittings and has been flushed and back flushed several times over a 4 day period. Mechanic told me it was head gasket or worse. I did some research and found there was no white smoke with moisture coming from exhaust, no water in oil, engine isn't missing. Did a block test couple of days ago and fluid remained blue, didn't even get a tinge of green and certainly not yellow. When I put a 50/50 mixture of dexcool back in I noticed it didn't seem to take very much before the radiator was full. I drove it approximately 5 miles and it climbed straight toward red zone ( where it had been fluctuating) so I shut it down before it got there. Let it cool for 8 hours and then poured in more coolant into radiator. (took less than a pint) and drove it back home. Temp reading was climbing up to red zone again so I shut it off as I turned into the driveway. Didn't quite make it to the red zone. Let it sit over night. One thing that I will add is that I noticed the upper radiator hose was really tight with pressure. My next step was to bleed the system. After bleeding for a while it was back to the fluctuating again and pressure on upper hose was much more normal. When the system cooled down the upper hose collapsed. Released pressure and hose went back to normal shape. The upper hose collapsing is a new situation. Anyway, next morning I added more dexcool mixture but before I did that I noticed the upper hose again had collapsed. I realize this is quite a bit of info of things done and ending results but I seem to be going from bad to worse and am at wits end. What would/could be the core cause of this malady? Let me add that there are no leaks from the system and it doesn't blow hot air from heater. Can anyone give me some ideas? Thanks.

**indygrandprix** · 08-03-2014

If your hose is collapsing you need a new radiator cap. Also you would have been better off switching over to green coolant when you flushed it.

If it's getting hot at low speeds and stopped but not at higher speeds then check if your fans are coming on. More than likely that is your culprit.

**johnj4654** · 08-03-2014

Originally Posted by indygrandprix

If your hose is collapsing you need a new radiator cap. Also you would have been better off switching over to green coolant when you flushed it.

If it's getting hot at low speeds and stopped but not at higher speeds then check if your fans are coming on. More than likely that is your culprit.

The fans are working and I just put a new radiator cap on. THe green coolant you mention is that just normal antifreeze and if so should I dilute it at 50/50 also? I just ran the vehicle for 15 minutes and it got up to the last notch before going into the red. The upper hose has what seems to me to be too much pressure. I have started bleeding it again, still a good bit of air between spurts of coolant.

**indygrandprix** · 08-03-2014

Well get all the air bleed out first. That could be your only issue. The air would cause overheating, the hose colapse, and would cause the system to have too much pressure.

You already bought the dexcool so just leave it in there but next time you flush your cooling system I would change over to green (normal) antifreeze.
Dexcool is NOT a 5 year/100,000 mile antifreeze.

**Russosaur** · 08-03-2014

Fwiw my rad hose collapsed when I did elbows and all I did was bleed the system and top it off with coolant and it stopped because it was low. Also I may have missed it but have you tried a new tstat?

Sent from the Milky Way

**johnj4654** · 08-03-2014

Originally Posted by indygrandprix

Well get all the air bleed out first. That could be your only issue. The air would cause overheating, the hose colapse, and would cause the system to have too much pressure.

You already bought the dexcool so just leave it in there but next time you flush your cooling system I would change over to green (normal) antifreeze.
Dexcool is NOT a 5 year/100,000 mile antifreeze.

Would you say the best way to bleed the air off is to use the bleeder on the thermostat? Also, if I pull the thermostat is it advisable or even possible to pour coolant directly into the block at that opening? How long does it normally take to bleed the system and should I see a steady stream of coolant or will it always alternate between air and coolant? I know this seems to be a dumb question but I don't have the experience with this activity and am clueless as to what to expect. Thanks for the help that you have provided thus far.

**Russosaur** · 08-03-2014

Here is Scotty bleeding guide, but yeah you can remove the tstat and pour directly in the block.

now to bleed the air out, let it idle rad cap off till the fans turn on, (when the fans are on the temp is over 195 deg, the t stat is wide open) then open the bleeder screw on top the t stat housing a few turns till a steady stream of coolant comes out the hole, shut the screw, top off the rad. cap it.

Sent from the Milky Way

**johnj4654** · 08-04-2014

To be sure I understand, bleeding the system should be done with the radiator cap off during the whole process, while looking for the steady stream of coolant from the bleeder on top of the thermostat? Thanks for the assistance.

**Frosty** · 08-04-2014

Originally Posted by johnj4654

To be sure I understand, bleeding the system should be done with the radiator cap off during the whole process, while looking for the steady stream of coolant from the bleeder on top of the thermostat? Thanks for the assistance.

My personal method to bleed out cars is to remove the rad cap and to unbolt the thermostat housing. Then I fill up the radiator as much as possible and also fill up the engine as much as possible through the thermostat hole. I replace the thermostat housing and fire it up without a cap. after 5 or 10 mins it will burp and I add the rest of the coolant. If it still overheats after that then you have a bad rad or thermostat ect ect.

**Russosaur** · 08-04-2014

Originally Posted by johnj4654

To be sure I understand, bleeding the system should be done with the radiator cap off during the whole process, while looking for the steady stream of coolant from the bleeder on top of the thermostat? Thanks for the assistance.

Yeah rad cap off, add coolant as needed. Make sure the fans come on before you crack the bleeder and you want a solid stream of coolant.

Sent from the Milky Way

**johnj4654** · 08-04-2014

Ok kind people. I have finally gotten the air bled out of the system. Thanks for your guidance. Now at low (idle) rpm the temp is slowly climbing above the halfway point and heat is still not working optimally. I ran the rpm up to 2200 when the temp gauge had risen to the second notch above the halfway point and it immediately fell down to the notch below the halfway point. Heat began to be at best lukewarm. Ran it like this for around 3-4 minutes and temp started to climb back up. I let it get to the first notch above the halfway mark and ran the rpm's up to 2700 and it dropped the temp gauge right back down to the notch below the halfway mark. Heat was working much better. What would you guys say is the cause of this? I'm not showing any visible leaking but haven't inspected the weep hole on the water pump to see if that is leaking. Does this sound like water pump or thermostat? See my opening post for all that has been done on this unit. Again thanks for all your help.

**Russosaur** · 08-04-2014

If you not getting heat you might have air trapped in the heater core because you said you had the hoses off and flushed and back flushed the core right? Can you hear like sloshing while driving by chance? Other than that, I have no idea if it could be a blend door actuator or if thats how it works to change hot from cold. Someone else would have to chime in.

Sent from the Milky Way

**johnj4654** · 08-04-2014

Here's the latest update: I drove the vehicle 14-15 miles. When at low speed or idle the temp would climb to the notch above midway. As long as I was running a consistent 50-60 mph the unit would sit at or just below the halfway mark. Still get no heat. Temp from heater is no different than if it is on the cold setting. I feel that the two issues are related but again I'm not a mechanic. On a side note, when the vehicle wasn't running I had accessories on and rotated the heat and cold selector and heard the motors that open and close the blend door. Also checked the vent direction ie floor, upper vents or both and heard the motor that makes those changes. I know that the door or flap that changes the vent direction is working as the flow of air changes with the selection.

As for your question about hearing sloshing, no I heard no sloshing while I was driving.

**dgjks6** · 08-04-2014

Been though this. Blocked heater core will not cause it to overheat. If you have replaced everything you said and checked the fans the only thing left is the water pump. Also I would put in a new thermostat. I have gotten bad ones from Autozone.

**Russosaur** · 08-04-2014

It honestly sounds kinda normal, mine runs at about 188-195 at speed and up to 212 just zipping around town. Got anyway to digitally read coolant temps, idk if your DIC shows it or not. The no heat still seems like the core has air in it or something or your rad is really low, I could be overlooking something simple iv been in the sun all day.

You can check for play in the water pump which could indicate its going out.

Sent from the Milky Way

**johnj4654** · 08-04-2014

Originally Posted by Russosaur

It honestly sounds kinda normal, mine runs at about 188-195 at speed and up to 212 just zipping around town. Got anyway to digitally read coolant temps, idk if your DIC shows it or not. The no heat still seems like the core has air in it or something or your rad is really low, I could be overlooking something simple iv been in the sun all day.

You can check for play in the water pump which could indicate its going out.

Sent from the Milky Way

No digital temp readout, radiator is definitely not low, unfortunately I can't see the weep hole on the water pump, , but still seeing no drips on concrete, so what is your thought on a bad thermostat as was mentioned by another poster?

**dgjks6** · 08-05-2014

OK, I just reread the entire post. I have you diagnosis. Take it with a grain of salt. I am not a mechanic but I did sleep at a holiday inn last night. You car is not overheating, just running warm (slightly above the halfway mark at times) and you have no heat.

My diagnosis is debris in the system. Your heater core is clogged by debris. Take off the lines to the heater core and flush with a hose. Reconnect and refill the system then bleed. This will solve the problem temporarily, but it will return. The debris is probably also probably blocking some of the radiator passages so flush it again.

Of a side note - in the process of tracking down my leak I replaced the water pump, thermostat and housing, elbows, LIM, water pump, heater core, and radiator hoses.

After all was said and done the car runs warmer (used to run a little above the first mark, now runs a little below halfway - it is always between the first and second mark just a little higher now (does that make sense)). My conclusion from this is that the aftermarket - read cheap - radiator I bought is not as good as OEM.

But after taking the system apart I found what people mean by dex cool causes problems. When I removed the lower intake there were places where there was no coolant flow that the coolant solidified. I suspect these pieces were getting in the system and clogging it.

**Russosaur** · 08-05-2014

You could try a thermostat they are cheap enough it wont be a huge loss if it doesn't work.

But to clarify, the car isn't overheating anymore it just doesn't have heat right?

Sent from the Milky Way

**johnj4654** · 08-05-2014

Originally Posted by Russosaur

You could try a thermostat they are cheap enough it wont be a huge loss if it doesn't work.

But to clarify, the car isn't overheating anymore it just doesn't have heat right?

Sent from the Milky Way

sorry for delayed reply, been out of town. The unit is still running hot just not nearly as bad and still no heat. Also should I get a 195 or 180 degree tstat?