Overheating AGAIN!!

Al H. wrote:

Is that an air bleeder valve?
If it is one it allows trapped air in the block to pass through the thermostat and be released from the system.
The old school method was to drill about an 1/8" hole in the outer edge of the thermostat, I still do.

that's what it is, is a bubble came up there, the valve would fall open and let it by, then the pressure would of the liquid would close it again.

Car is running about 165-170 now. Road trip to the keys tomorrow (bout 400 RT), ooil change when I return.

John,I always change the oil with the engine hot before the trip not after.Curious why you are
waiting?
Jim

brokecello wrote:

The rad can still hold pressure and still be bad/blocked...did you check it? Is it the old stock unit? Mine looked fine until I took it out...

I think I'm there at this point. Stupid thing is overheating again.........sometimes. it's weird. No leaks but after two weeks, it'll over heat and when I pop the cap it'll take a gallon or more.

the oil is fine too. It's really annoying......

Jim, the reason I didn't change the oil was that at the end of the trip it'd be at the 3K mark. If I were at 2.5K and doing a thousand mile trip, I'd change it first. For me a 400 mi R/T is a commute (do it fairly often).

Sorry John,forgot how much traveling you guys do.Takes me a year to drive 3000 miles.Wish I
could travel like I use to but my back wont allow it anymore.
Jim

Looking at the video on Fail Safe's website, they appear to have a pair of locking tabs that hold the plunger open if the stat moves too far open. Sounds good in principle, but on a hot day with the air on, I can see where the things might go into their locked mode just because the engine temp has crept up above the thermostat temp. Too bad; they seemed like a good idea.

John,. your tbi intake might be leaking coolant into one of the front two or rear two intake ports,.pull the plugs and look,. the really clean plug is where your problem is,.


Nick

Sprocket wrote:

Well it ran fine on the way home (35-40mph for 5 miles with some lights - suburban driving)


Temp went up to 190 and the tstat opened and it dropped back to about 180 which is normal.... got home popped hood, no visible leaks, unless I have a pinhole and it's not dripping and over time it goes down to nothing.

After the bad stat, I did find one very small 'pisser' leak in the 1991 only auto climate control metal pipes (since cut completely out of the loop ....no heat or temp control on the AC now), I may have another hard to find one.... Well driving it 5-=60 miles tonight should be a good test ha ha ha.

Just going to bring two gallon jugs of water with me

I have a 93RMW and had a very similar problem. On Start up from cold it would raise up in temp right up into the red. I'd pull over shut off (just before red) and sit a minute, start up again, and totally stable. I could drive all day without a spike or a temp above normal. Same thing every day. We checked everything... or so I thought.

Changed out the thermostat, same. Finally they said it was my gauge and to ignore it. Instead I ran a 2nd temp gauge from a hot rod pod from autozone to prove it was getting hot.

The pulled my head to see if it was clogged. Sick if it and out of money, I had them drill 4 small holes in the thermostat and problem solved. Flow no mater what. Barely better than running without one at all.

Two days and 1200 bucks later, a leak! My bottom radiator hose was leaking around the radiator and it was SOFT AS BUTTER!

They didn't check the HOSE!

When the car gets hot, its was vacuuming flat (i watched it) then once even, it would kick out and flow fine.

Something to consider. Hope it helps.

VacFink

thanks for the tip Nick, will pull the plugs this weekend and check....

93RMW wrote:

They didn't check the HOSE!

When the car gets hot, its was vacuuming flat (i watched it) then once even, it would kick out and flow fine.

This is the reason people think that if you push coolant too fast through a radiator, it won't cool as well. It's not because of that at all. It's because the pump creates too high of a suction for the plumbing to supply it, and cavitation and/or lower hose collapse starves the engine of coolant when the pump revs too high.