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Black Beauty 2.0 (06’ 300c 5.7)
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Discussion Starter · #1 · (Edited)
Sooooo story starts that the car was completely fine and not rising in temp like it is now. This started because the other day when it hit 108 degrees outside here in Texas and my car was running hotter than usual, the car hit around 230 degrees but the temp needle didn’t move from the halfway mark and the digital reading of the engine temp went down to the normal 220 degree range after a few stop n go traffic lights. So I tried burping it the old fashion way with the reservoir cap off and letting it run with the heat on when I got home, to see if maybe there was air in it as I’m an over thinker, after about 20-30 minutes the coolant started to spew out the reservoir so I quickly turned off the car then capped it after but the car was at normal temps the entire time I was letting it sit!! Woke up the next morning and poured more coolant in as a bunch came out as previously stated, turned my car on and did the burping process again and it still ran fine with no rising temps but I also didn’t put as much coolant in the reservoir so it didn't spew out again from it over filling, turned off the car and went back in for the day. Now this morning when I woke up I put coolant in it to the cold fill line and drove it, i barely made it out my big neighborhood and I saw the needle started to slowly climb up past the middle mark and the digital reading was 233 degrees so i quickly pulled over and inched it home after a few stop and go cool downs. I let it sit for a few hours then tried burping it again at an incline and I did see bubbles coming up but then the temp needle started to slowly climb up and the digital reading was reaching 230 degrees so I capped it because coolant was also overflowing as of course I was letting the bubbles come up out the reservoir… maybe I added too much coolant??? I only filled it slightly passed the cold fill line. Don’t know why it spews so much sometimes.

Some factoids:
- I’m not loosing coolant that’s noticeable except seeing some old coolant build up from where the top of the thermostat meets the water pump, which I just noticed as I haven’t been under the hood in a few months or so (a shame I know face palm … been busy with my other cars!)

- heater works just fine and blows hot like normal

- oil looks good and is clean

- coolant looks good and is clean, replaced coolant completely with ZEREX G05 about 8-9 months ago when I replaced the water pump!

- I noticed my fans kicked on immediately this last time I tried burping the car on an incline even though the engine temp was only at 125 degrees when I started it and the AC button was off and heat turned all the way up, is this normal????

Any ideas ANYONE? Please and thank you! Want to get this resolved! Could the smallest of leaks from the thermostat be why my car is now WANTING to overheat after a doing a random burping process? Why all of a sudden??? But then run normal but then overheat again when driving it? Bad tstat?

PICS BELOW ARE OF BUBBLES COMING OUT RESERVOIR THIS LAST BURP PROCESS AND THEN THE COOLANT BUILD UP ON TOP OF THERMOSTAT I FOUND.
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"...about 8-9 months ago when I replaced the water pump "

didn't hear you mention the t-stat.... was it new with the water pump or did you re-use? Also, are the fan blades in good shape... any tune that effected fan settings, do they come on as they should... Belt tension is ok for the water pump? Likely you're already on top of these things, but these are the thoughts your post brought to mind
 

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Black Beauty 2.0 (06’ 300c 5.7)
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Discussion Starter · #3 ·
"...about 8-9 months ago when I replaced the water pump "

didn't hear you mention the t-stat.... was it new with the water pump or did you re-use? Also, are the fan blades in good shape... any tune that effected fan settings, do they come on as they should... Belt tension is ok for the water pump? Likely you're already on top of these things, but these are the thoughts your post brought to mind
Yep, Brand new $20ish dollar tstat along with water pump and radiator hoses from the autozone a few min away from me, replaced a few bad hoses near the firewall as well. Only thing that isn’t new is the thermostat housing and the radiator and fans. Car is on stock tune with stock 203 degree tstat. I will actually have to check the tension on the belt, staying at my girlfriends place tonight and brought my 5.0 so can’t check right now. Fans do both work and are in good shape, I did notice that when I turned on the car this last time around to burp it, with the heat on full blast and ac off, the fans instantly turned on??? The engine temp read 125 degrees when I started it up. Is that normal? New to mopar so maybe I’m just overthinking.
 

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So.... several things.
Why does it someone smeared red rtv around the Thermostat housing?
Stock Thermostat?
Are you reading actual Coolant temp? Or the dash gauge? Iirc, the factory temp gauge reads oil temp, not Coolant.

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Black Beauty 2.0 (06’ 300c 5.7)
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Discussion Starter · #5 ·
So.... several things.
Why does it someone smeared red rtv around the Thermostat housing?
Stock Thermostat?
Are you reading actual Coolant temp? Or the dash gauge? Iirc, the factory temp gauge reads oil temp, not Coolant.

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Stock thermostat and yes that is in fact a butt load of RTV, mechanic did that as he said it’s an issue with tstats leaking on these cars (the irony). I’m reading the “engine temp” based off the EVIC menu and just looking at the temp needle. Going to replace the thermostat with a higher end one with stock oem temps although 180/190 seems to be a great “mod” on mopar forums so debating, and probably replacing the housing as well just for extra precaution.
 

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If you are on the normal evic menu, I think it's still oil temp. Unless you are on the "hidden menu."
Do the 180 thermo, and Tune to change the fan settings.

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Black Beauty 2.0 (06’ 300c 5.7)
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Discussion Starter · #7 · (Edited)
If you are on the normal evic menu, I think it's still oil temp. Unless you are on the "hidden menu."
Do the 180 thermo, and Tune to change the fan settings.

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Yes I am under the hidden evic menu. What advantages does the 180 tstat do for our hemis? I always hear how the hemis were made to run hot like the normal 210-220 area?
 

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"What advantages does the 180 tstat do... "

Our early hemi's have a rep for dropping valve seats when they get hot. Running a lower temp t-stat and changing the fan settings provides a bit more buffer in the event things start to over heat. It's also a popular thought that Chrysler had to run the engine hot to meet standards. The lower temp stat is more familiar thru the years and were it not for regulations, Chrysler wouldn't have run it that high. At least these are the take a way's from what I've read... others may have more info.

For myself, I'll make the change when my waterpump & t-stat need to be replaced. It's run fine for 160k+ miles/17 years and so doesn't appear to be a design flaw. A Diable i3 was bought to turn off mds (problems) for my ride, and so I already have a means to adjust fan settings. Just replacing the t-stat won't do anything by itself...
 

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Black Beauty 2.0 (06’ 300c 5.7)
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Discussion Starter · #9 ·
"What advantages does the 180 tstat do... "

Our early hemi's have a rep for dropping valve seats when they get hot. Running a lower temp t-stat and changing the fan settings provides a bit more buffer in the event things start to over heat. It's also a popular thought that Chrysler had to run the engine hot to meet standards. The lower temp stat is more familiar thru the years and were it not for regulations, Chrysler wouldn't have run it that high. At least these are the take a way's from what I've read... others may have more info.

For myself, I'll make the change when my waterpump & t-stat need to be replaced. It's run fine for 160k+ miles/17 years and so doesn't appear to be a design flaw. A Diable i3 was bought to turn off mds (problems) for my ride, and so I already have a means to adjust fan settings. Just replacing the t-stat won't do anything by itself...
Perhaps I should of bought a 180 tstat instead when I replaced my tstat and water pump along with many hoses. I’m new to hemi’s. Just can’t imagine a thermostat going bad so soon or maybe the gasket where the housing meets the water pump is faulty. Either way I should of just left it alone as I wasn’t having issues until I tried burping it but then it started spewing out like crazy from the reservoir so I turned off the car then I capped it after (Face palm). But then it ran fine when I tried burping it the 2nd time around just with less coolant so it didn’t overflow on me and spew out again.
 

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Opinions are like a$$holes right.........so here's mine. :)

If the coolant system was opened up, but the proper burping wasn't ever completed to get all the air out of the system, then I think that's your issue here.

When I changed out my 180 stat for a 160 on my old Durango R/T 5.7, the temp gauge went all wacky on me right after I put it all back together. It stayed that way until I properly removed all the air.

I purchased this kit (or similar) online and used it with success.

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Temp gauge sat right in the range it was supposed to. All was good.
 
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Discussion Starter · #13 ·
Opinions are like a$$holes right.........so here's mine. :)

If the coolant system was opened up, but the proper burping wasn't ever completed to get all the air out of the system, then I think that's your issue here.

When I changed out my 180 stat for a 160 on my old Durango R/T 5.7, the temp gauge went all wacky on me right after I put it all back together. It stayed that way until I properly removed all the air.

I purchased this kit (or similar) online and used it with success.

View attachment 177485


Temp gauge sat right in the range it was supposed to. All was good.
May have to give this a shot since I don’t usually trust bleeder screws on cars, never get the full air out that way in my experience, cheers 👍🏼
 

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I do both methods in one. Do at least a few heat cycles before driving.
Never had the greatest luck with duralast Thermostats.

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Discussion Starter · #15 ·
I do both methods in one. Do at least a few heat cycles before driving.
Never had the greatest luck with duralast Thermostats.

Sent from my SM-G988U using Tapatalk
Which tstat are you running and would you recommend? Searching through the forums there’s a handful amount of people who have had bad luck with tstats failing often. Maybe a hit and miss.
 

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Discussion Starter · #16 ·
Opinions are like a$$holes right.........so here's mine. :)

If the coolant system was opened up, but the proper burping wasn't ever completed to get all the air out of the system, then I think that's your issue here.

When I changed out my 180 stat for a 160 on my old Durango R/T 5.7, the temp gauge went all wacky on me right after I put it all back together. It stayed that way until I properly removed all the air.

I purchased this kit (or similar) online and used it with success.

View attachment 177485


Temp gauge sat right in the range it was supposed to. All was good.
Which Tstat would you recommend? Do I NEED a tune to change the fan settings? or would just changing the tstat to a lower one and a few burps be good? Also just noticed the temp of the air coming out my passenger side vent is always cold, even when both controls are set to high heat. Would that affect the old school burping process? I would figure no since my driver side vents blows hot just fine. Can’t wait to be back home to tackle this issue
 

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How are you bleeding your system? Are you removing the bleeder screw on the water pump filling up until you see the coolant come out. i have had the same problem before . If you fill up with out removing the screw you will get a bubble in the system and it will heat up with in a few miles. I would do a compression check to make sure you didn’t drop a valve seat. I f it is only overheating you maybe okay. If it’s running poorly then you could have dropped a valve seat.
 

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Discussion Starter · #18 ·
How are you bleeding your system? Are you removing the bleeder screw on the water pump filling up until you see the coolant come out. i have had the same problem before . If you fill up with out removing the screw you will get a bubble in the system and it will heat up with in a few miles. I would do a compression check to make sure you didn’t drop a valve seat. I f it is only overheating you maybe okay. If it’s running poorly then you could have dropped a valve seat.
Car was running fine and all, it just ran hotter than normal one drive on a hot day here in Texas and ever since I tried burping it out of precaution, the old school method of letting the bubbles come out the reservoir, it’s been a headache ever since but for sure new tstat and seal is needed just need to get back home and have time to tend to that car, been doing maintenance on the wife’s Chevy Cruze.
 

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Car was running fine and all, it just ran hotter than normal one drive on a hot day here in Texas and ever since I tried burping it out of precaution, the old school method of letting the bubbles come out the reservoir, it’s been a headache ever since but for sure new tstat and seal is needed just need to get back home and have time to tend to that car, been doing maintenance on the wife’s Chevy Cruze.
it sounds like you have a air bubble in the system . if you look on the water pump you will see a hex screw on there . Back out and remove it. Once it’s out , fill system and when it starts coming out with pure coolant you should be good. Install the hex screw and should have all the air out. I’ve build several hemi and have had problems with overheating if I don’t bleed this way. Good luck.
 

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Hi mate;

I concur with the guys above, likely a burping problem, as long as temp has not damaged anything.

Whenever something happens on a car and someone brings it to me, first thing I say is "what has changed??" Because "Car running fine, do something = have problem" - SOMETHING is where the likely start of it is.

I have had people say "They did xxx, but couldn't be that, because they fixed it..." But car was fine until then???

Firstly, I am old and I don't trust anything. The thermostat. Your car ran fine before, now it doesn't AFTER new thermostat. I always test "new" things. ONCE (ONCE!!!!!) I didn't test a radiator cap on an old car, meant to be 13 lb. It blew the hose off. When tested, it was 19 lb. These items are cheap, and remarkably reliable, but every now and then get a dud.....................So - I would test the thermostat. MAKE SURE it opens when it should. Just boil it on the stove with a thermometer in the water, watch when opens, make sure it opens all the way. Make sure temp isn't reading direct gas from stove etc etc (you know the drill).

Secondly, temp gauge. Good to read the EVIC temp, that should be ok. I would double check. IR temp checker is 8 dollars, or $20 if you "get a good one". Be careful as different surfaces give different readings sometimes, but take a heap of readings, can work out what is spurious.

The temp gauge in new cars often isn't linear. Otherwise people would panic. As these engines run hot; the "operating range" they are meant to run within is compressed in the middle of the gauge, and is a component of the engine monitoring "showing what people want/need to see". That is why the needle goes to about the middle, then hardly moves as temp wanders up. When the computer gets to a "warning temp"; it will then elevate the gauge, but often by then warnings (lights, even codes) will start to take over.

The point is, the gauge will sit "at normal" for a bit of a range that it deems "normal"; so if you want to see any movement, use the EVIC, (which you are, great) once you confirm that THAT is correct.

Remember that EVIC can only read correct temp if correct circulation, otherwise it will be a "hot spot". Fan belt tension, water pump (incorrect clearance, but yours new????), thermostat not opening/not opening far enough can all cause that. Again, IR will show if temp even throughout or not. Is radiator red hot when it is doing this? The average old blokes hand can tell the difference between "Hot" (normal) and "HOT hot" (overheat)..............

I would remove thermostat and test. Test the old one. See if any difference. THEN I would burp again, go from there.
 
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