Running thinner oil raised temps?

[nemo]

WOW! Not until post 28 was low coolant level mentioned. That should have been the first check.

Balto

Old Mechanic is giving you some great advice.

[RobertISaar]

Originally Posted by ksa8907

No pressure=no cooling.

so, what's the science behind this?

pressure in the cooling system only does one thing effectively, and that is raise the boiling point of the coolant used. it does SLIGHTLY increase how effectively the coolant transfers heat, but not significantly. a 50/50 mix at atmospheric pressure won't boil until ~223*F. for every PSI that the coolant is subjected to, the boiling point raises about 2.5*F. so 14PSI(pretty common radiator cap rating) is about 262*F.

it's also worth noting that water has a better thermal coefficient than antifreeze... running more water in proportion WILL result in more heat transfer from head/block to coolant and from coolant to radiator.

[Baltothewolf]

Originally Posted by Old Mechanic

I'm guessing you cut the top hose?

Absolutely use your uncle's car to get the antifreeze, then top the rad and bottle (at least 3/4 of the bottle) and drive it just enough to warmup. I'll bet your temp drops just from those actions.

Dont worry so much about responding to every post. it may take a few days to "burp" it. Absolutely watch for any leaks. I had one in my 99 Maxima. Drove it 400 miles and it never ran hot but I kept having to add coolant and finally spotted a leak at the top of the radiator, and replaced that day.

The coolant level was just low enough for it to not leak, it only leaked when I topped it up several times. I'll be here or in the ground.

regards
Mech

Ok well no luck on adding fluid. Drive home, if I turned off the A/C trick you told me to do, I will slowly climb to 250F. I turn the A/C on (with heater on max) and it drops down to 210F. I'm at a complete loss.

Also, yea, I cut the top hose.

P.S Yes I topped off the resevour thingy with antifreeze.

[2000mc]

are all grill blocks removed?

when the car is at 210 or higher, and the fans are on, open the hood and hold your hand in the stream of air being blown off the fans. is the air too hot to comfortably leave your hand in the air steam, or is it barely lukewarm?

[Baltothewolf]

Originally Posted by 2000mc

are all grill blocks removed?

when the car is at 210 or higher, and the fans are on, open the hood and hold your hand in the stream of air being blown off the fans. is the air too hot to comfortably leave your hand in the air steam, or is it barely lukewarm?

Radiator fans don't kick on unless A/C is on. And yea grill block has been removed for a while.

[2000mc]

so... after the car is at 210 or higher, turn on the a/c, open the hood and hold your hand in the stream of air being blown off the fans. Is the air too hot to comfortably leave your hand in the air steam, or is it barely lukewarm?

[Baltothewolf]

Originally Posted by 2000mc

so... after the car is at 210 or higher, turn on the a/c, open the hood and hold your hand in the stream of air being blown off the fans. Is the air too hot to comfortably leave your hand in the air steam, or is it barely lukewarm?

Uncomfortable, can't hold my hand there for longer then 15 seconds before it starts to sting from the heat.

Also, @Old_Mechanic, my upper rad hose I can't even touch without getting instantly burned. I had my dad who has tough hands touch it and he could only touch it for about 1/2-1 second before he had to take his hand off. I also just replaced the radiator cap and obviously, it did nothing. Fluid levels were fine as well before I drove it so no bubbles I don't think. I'm even more lost now...

[ksa8907]

Originally Posted by RobertISaar

so, what's the science behind this?

pressure in the cooling system only does one thing effectively, and that is raise the boiling point of the coolant used. it does SLIGHTLY increase how effectively the coolant transfers heat, but not significantly. a 50/50 mix at atmospheric pressure won't boil until ~223*F. for every PSI that the coolant is subjected to, the boiling point raises about 2.5*F. so 14PSI(pretty common radiator cap rating) is about 262*F.

it's also worth noting that water has a better thermal coefficient than antifreeze... running more water in proportion WILL result in more heat transfer from head/block to coolant and from coolant to radiator.

The science is that when water boils a pump isn't very good at moving steam. And yes, water has a higher heat capacity. Merely stating that if you have water in your coolant and a bad pressure cap, you are more than likely overheating. This was determined not to be the problem.

Have you replaced your thermostat? If you are indeed losing coolant and its not on the ground it could be a headgasket issue, they make a tool that measures hydrocarbons in the coolant for easy diagnosis.

[XYZ]

Originally Posted by Baltothewolf

Radiator fans don't kick on unless A/C is on. And yea grill block has been removed for a while.

Sounds like your primary cooling fan isn't coming on when it should. If both fans run when the A/C is on, it's not the fan itself that is the problem. It's either a sensor or a relay in the system that isn't turning the #1 fan on when needed.

[oil pan 4]

Whats the derence between an unpressurized system that boils at 223'F and a pressurized system that boiles at 260+'F?

Nucleate boiling.
Just because the temperature guage says 200'F or 220'F doesnt mean that is the hottest part of the engine. In side the water jacket inside the heads surfaces around the combustion chamber and exhaust port routinely hit 250'F and can easily climb to 280'F.

Then this can happen:

http://www.youtube.com/watch?v=TDD8TZxwFCg

And then your cylinder head cracks.