when something doesnt make sense... and you finally figure out why !

[Jer]

Try to shorten this story up, last summer the wife & I attended a bbq in our 74 Midget, of course it was a stupid hot day & I was rushed & neglected to open the heater valve before we headed out... the car held it's temperature just half way on the gauge until the last couple miles where we were crawling/backtracking finding the cottage... then it climbed up to the 3/4 mark, but no steam or gurgling, after we arrived & I was unloading the trunk the temp gauge had then pegged as the car was shut off & no circulation... but it was off & in the shade so I left it as there wasn't much I could do at that point.

When we left hours later the car started fine & was running okay, shortly after heading out I noticed that the temp gauge still hadn't moved off of "Cold", I figured the gauge was busted from being pegged as the car was running okay & the motor wasn't hot & had good oil pressure... about 1/2 hour into the 1 hour drive the car started to miss really bad, if I drove slower it wasn't as bad but still "bad", then shortly after I noted white smoke out the back, by then I was a couple miles from home, just kept an eye on the oil pressure & limped home...
Next day I check the coolant level, only down about 1.5 quarts, oil is full, not miky, none of the sparkplugs are "steamcleaned", with the engine cool (it had such a bad miss I couldn't even let it warm up) I had balanced compression (can't remeber exactly but around 150), I pressurized each cylinder with 120 psi (on compression stroke), no issues... So I figured that the head gasket was leaking a bit when the motor warmed up, no big deal I had a spare payen on the shelf but the horrible miss had me baffled... all winter baffled.. as "life" has been a bit silly the past year... anyways this past weekend I pop the hood & start wondering if something happened to the ignition by fluke at the same time I had lost the head gasket... then by dumb luck I noticed the ground wire had come out of the connector on the coil (I have a petronix unit) - Son of A @!$%& !!! I was so focused on the overheating causes I didn't look for the obvious... repaired the connector, **** car fired up fine, no miss & sure enough once it warmed up it started blowin white smoke, but hopefully can be fixed by a new headgasket, it makes so much more sense now !

Just thought I would share as a reminder for us all to take the "blinders" off & think simple ! ;-)

 

[SaxMan]

When I blew my head gasket, the blanking plug between the #2 and #3 cylinders recessed into the head. If you don't fix that, you'll blow the gasket again. My head gasket also blew when I pegged the temperature gauge -- had an air pocket in the system when I changed my thermostat, so ended up being low on coolant.

The old thermostat was fine, but the car always seemed to run cool. The new thermostat yielded no different results, and I toasted the head gasket to boot. That was my first real lesson in what happens when you go looking for solutions to things that aren't problems. Two and a half years later the car still runs cool. I can sit in traffic on a 90 degree day and never cross the halfway point on the gauge.

I've found with cars, as well as musical gear for that matter, that the more catastrophic the failure, the more obvious (or simple) the cause actually is.

 

[nomad]

A lot of thermostats now days don't have air bleed holes. If I get one without the bleed hole I always drill a small hole...say 1/16. That way you are sure that no air pocket exists when you are filling the system. If there is nothing but air under the thermostat it can't sense the heat accurately and that can only add to the problem. Overheat guaranteed!

Kurt.

 

[dklawson]

A lot of thermostats now days don't have air bleed holes. If I get one without the bleed hole I always drill a small hole...say 1/16.

That reminded me of an old "Puzzler" question from the Car Talk radio program. The brothers presented a situation where their lead mechanic "Crusty" was using aspirin in the shop but not for headaches. The actual use was to wedge a new thermostat open when the cooling system was being refilled. The aspirin held the t-stat open allowing air out and coolant in, then dissolved to allow normal operation.

 

[nomad]

That reminded me of an old "Puzzler" question from the Car Talk radio program. The brothers presented a situation where their lead mechanic "Crusty" was using aspirin in the shop but not for headaches. The actual use was to wedge a new thermostat open when the cooling system was being refilled. The aspirin held the t-stat open allowing air out and coolant in, then dissolved to allow normal operation.

I'll have to remember that one! Wouldn't have to sacrifice the bleed through the hole during warm up! Seems the thermostat springs are pretty stiff though so it could be one of those "urban myth's".:rolleye:

Kurt.