Hot...Then, Not.

ddoan

ddoan

Star Shooter
Well, after a couple of months, since we solved the no-start problem (remember the faulty ECM's?), my wife and I took our first long trip this weekend. We travelled from our home in Morgan Hill, to our daughter's home, in Paso Robles - about 130 miles each way, on the 101.

The trip down was uneventful. The car handled perfectly. The trip back (today) was a little unnerving for a few minutes. About 45 minutes from home, it started raining, and the cabin was getting a little stuffy and the windows were fogging some. So, I pushed in the heater button and slid the lever to the cool setting, and turned on the fan. I wanted some outside air, in, without lowering the windows.

Almost immediately, the temp guage began to rise. As soon as I saw it, I slowed from 75 - 60 mph and got over to the right lane - sort of coasting. Then, the temp began to lower - back to it's normal 180 range. I breathed a little easier, and suddenly, it nearly maxed out, again. Same routine - slowed down, and the temp dropped to normal. And, that was it. Traffic was heavy, so I couldn't speed, anyway - kept it at 60 the rest of the way home, but I did smell anti-freeze for a little while.

My mind was racing to figure out what had happened. Head gasket, blown or leaky hose, plugged radiator? Keep in mind, this all happened immediately after fiddling with the heater switch.

When we got home, there was no evidence of a blown head gasket. Upon checking after the car cooled, there did not appear to be any loss of coolant. There was no coolant on the engine.

My thought is that I might have gotten a temporary air lock in the coolant lines, somehow. Tomorrow, I'll bleed the system (as I did before the trip) to see if there are any air bubbles in there. But, I'm also interested finding out your thoughts. Am I missing something? Here's a photo I took on Friday - it's an '84 FI car:

x.jpg


Thanks,

Don
 
nearly the same thing happened to me today, except I had the heat on, top off and I know I lost "some" coolant when I had the carb of last week.
 
When you bled pre-trip...

Hi Don,

When you bled pre-trip did you do so with the heater on, fan on high and while revving the engine? You might have had a big air pocket in the heater lines or core. Any air pocket in the heater loop would pass right thru the block. Sounds like whatever it was worked its way to the res tank or the rad. Listen closely when you bleed the radiator and see if hear any air escaping.

Good luck and hopefully it was just a bubble. :)
 
Do you have the plastic splash guard below the crank pulley installed?
I once had this removed and and my car overheat in the rain because the belts were getting wet and slipping... BTW, you have a great looking car.
 
Don,

Sounds like air in the system that needs to be let out. Funny; I ended up taking a trip to Monterey this weekend myself when I couldn't get the car together for the BOFI trip. Not quite as far but a nice trip just the same.

The rain can play tricks on your belts as Mark points out. I also drove home in the rain - it was coming down like cats and dogs on highway 1. My car ran cool but I could hear a belt "chugging" so I can see where it could make your water pump belt slip.

As many others have pointed out (to me) you typically need to bleed the system a few times before its 100%.

BTW - Sydney says hi!
 
About 99% of the time

So, I pushed in the heater button and slid the lever to the cool setting, and turned on the fan. I wanted some outside air, in, without lowering the windows.

Almost immediately, the temp guage began to rise.
Click to expand...

This happens because you had air in the heater core or heater lines, and when you turned on the heater that air was free to be swept into the radiator. Next time the engine is warm, turn the heater on and rev to about 3000-4000 rpm for a few minutes to force some serious circulation through the heater - and then bleed again.

If this keeps happening, you may have a leak in the heater loop. That's the 1% possibility.
 
I'll Re-Bleed

Thanks, guys.

I did not bleed the system with it hot before the trip. I did open the bleed valve with the heater in the on position, but the coolant was cold. I'll definitely do it now after running the car for a while. I'm guessing that the air worked itself out, but I'm not taking any chances.

I hadn't heard of the belt slippage issue before. And, no the car doesn't have a splash guard below the crank pulley. Anyone got a photo of that?

Tim, back at Sydney! My other tractor is running great, now. Bring her over and we'll do another ride. Glad you were able to work things out with the insurance company.

Thanks to those who commented on my car's "good looks." It's been running great for a couple of month's - since the ECM problem got resolved. I jacked the idle speed a little last week - and started using 91 octane - and was surprised at how much quicker the car is.

Don
 
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