boil over/not over heat

[chucks97expy]

Hey everyone, just had something strange happen last week. I had a boil over but my temp gauge showed I was fine. Happened a couple more times but each time it would boil over and then the truck ran fine. I would lose just a little fluid each time but not a lot. First thing I did was check the forums. A lot of guys were talking about head gasket failure and it causing excess gasses to leak into the cooling system to cause over pressure and the boil over. I hoped that wasn't it! So I started on the cheap, first thing I did was change the thermostat. The truck calls for 195degree so that's what she got. I bought the "fail safe" at auto zone for $25. Topped off the anti freeze 50/50 always and it did it again. Keep in mind that I have already changed the heater core, radiator and water pump within the last year. I felt the top radiator hose, it was cool to the touch. I felt the water neck that was holding the new thermostat and it was hot. So the the fluid wasn't flowing. I thought for a bit, maybe to hot of a thermostat? I went on Ebay and bought a 160 degree thermostat from Jegs $10 and also a new radiator/overflow cap. Installed them and topped off the fluid again and this time NO boil over! She's running great now! I haven't had a problem since. If anyone has had this problem I hope this might help out. By the way my heat is just as good as it was with the hotter thermostat installed. Maybe she's just getting old and needed a cooler stat? haha

 

[01yellerCobra]

More then likely it was the radiator cap. The spring gets weak and can't hold the pressure. I'd go back to the stock temp thermostat.

 

[chucks97expy]

Would have thought the radiator cap too except that the fluid wasn't circulating "at operating temp". Heat works great! so I'm just gona leave it unless I lose the heat.

 

[Yudaman]

160 degree t-stat????
Holy crap man! That's going to cause you problems down the road! Do yourself a huge favor and get the proper temp t-stat back in.
160 degree is far too cold and will result in being open most all of the time during normal operation. Your coolant will circulate through the system too fast and not have time to cool in the radiator, therefore cause you overheating problems. Not to mention, the engine running too cold and losing efficiency.

 

[Bedrck47]

Kindly post how well the lower rated T/Stat does in those cold windy days in winter when the temps are in the single digits that Chicago is known for.

 

[chucks97expy]

Hey guys, i'm happy to update that it's been three weeks and I haven't had any problems. To reply to Yudaman first, the water pump circulates the antifreeze through the motor into the radiator. The 160 degree stat holds the anitfreeze back until it reaches 160. The reason for a higher T-stat is for heat. That's it. Overheat because its flowing to fast through the radiator? you got me on that, never heard that happening to anyone. A car runs cooler on a cooler thermostat. As for efficiency? seriously? you can ask anyone on here and no one is getting 20 miles to the gallon haha! I gave up efficiency to own a big truck and I thank everyone who owns a little car that gets 40 miles to the gallon for keeping the fuel prices down haha....anyway the cooler the T-stat the less time it takes to open and the heat isn't as hot(usually) but I have news for all the neigh sayers....my heat works great! This weekend here in the windy city it dropped to around freezing and I got heat like I had the 195 stat installed. Oh by the way I have a 99 corvette 33,000 miles with a 160 stat(of course I dont drive it in the winter) and I also own a 06 chrysler 300 with the hemi 65,000 miles, that I installed a 160 in a few years ago. I haven't had a problem with any of them. What works for me may not work for you but I simply wanted to post the problem I had and that it seems to be fixed.

 

[Bedrck47]

again I will ask you to post the figures when you get those cold windy days in dec, jan. and feb that Chicago is noted for

I currently have a 195 deg stat in my 01 without any problems however I did have to change the old stat as it wasn't allowing the engine to come up to temp

Gauge now comes up to about half way before with the old stat gauge would only come up to about 1/4 the way
Attached was taken in Jan 2015 outside temp was in the low 30's

No problem with coolant temps or any kind of overflow problems

If you can not produce similar figures then I would say you have other problems

 

[chucks97expy]

I will post when those days get colder but for the time being I have no problems. The 195 just didn't seem to open soon enough. I never had an overheat problem just a problem that seemed to be to much pressure on one side until it pushed through the radiator cap and at that point it must of gotten to 195 because then it would circulate. My gauge reads just under half way with the 160 stat now and my heat is excellent. I have no boil over problems, no check engine lights(never did) and she's running like a champ.

 

[Bedrck47]

as you can see my temp was over 200 and the highest I have seen it go was 214 deg's
I can observe those readings and watch the temps come up and when the stat opens watch them drop I normally will see that happen around 198 to 214 degrees and again no problem with boil over or overheating

BTW I use a Bluetooth OBDII adapter and the Torque Pro app connected to either a smart phone or a tablet which allows me to take a screen shot similar to what I posted

 

[Bedrck47]

Before I changed stats I was only getting about 165-170 temps and had plenty of heat but now with the temps running around 200 I have more heat and have even set the auto temp to a different setting and run the fan at a lower speed as I can get it to roasting in the expy