Can't take car on long trips in Hot Summer

Hi,
I have a problem that I’ve heard twice on Car Talk. One call they had no answer, the next time they had the same obscure answer I have for my car, so I feel in good company, but alas I have no solution for my car (2000 Subaru Legacy Outback 4 door, white).
Two years ago we drove from NW Arkansas to east Texas in the hot summer. After a few hours we made a pit stop. Came out and car was dead, no click, no nothing. Opened hood and waited a few minutes and the car started. This exact sequence of events happened twice the following summer and once to me this year. The first time we had the battery checked and it was OK. It’s never happened when traveling in moderate or cold weather.
My inkling is that something that should be closed (electricly) is open from the heat. When it cools enough it closes and the car starts. It only takes a few minutes with the hood open.
The dealership says they can’t (duplicate it or) fix it when it’s working and I can’t let them take off for a road trip just to diagnose.
Does anyone know of any common things to look for that might cause this problem? I was thinking of taking a heat gun to different components if I knew what to try. Can a battery test good and act like this under extreme hot conditions?

Thanks in advance!
BK

If the battery checks out…it could be the starter…Sometimes starters won’t work when they get hot…I had a 70 F-150…that had this problem…The starter was within inches of the exhaust manifold…After long trips the truck wouldn’t start…I replace the starter…and the rebuilt starter came with a heat shield (gee why didn’t Ford think of that). Never had a problem again.

Yea I remember that now on an old Ford pickup. When that happened to you was it dead silence when you turned the key? I’m not hearing any relay clicks or anything when this happens to me.
Thanks

My dad had a similar issue with a '78 Buick Le Sabre many years ago only his would turn over extremely slow. The problem ended up being resolved by putting an over sized radiator on it. When you turn off the ignition the engine immediately heats up and causes internal engine parts such as pistons to expand causing more drag, if the cooling system isn’t sufficient this would explain why it starts after cooling down for a while and the parts begin to retract again. This may or may not be your problem, but just wanted to share this experience.

I don’t think you will need a new starter. Many Japanese cars use a spade connector for the ignition (small) wire to the starter. If this backs out enough, it will cause this condition. All you have to do is push it on.

Make sure the connector is going on and not the sleeve moving. Sometimes the sleeve will move while the spade itself does not. It makes you think it’s all the way on.

Another possibility, the park/neutral or clutch safety switch could be acting up in the heat. If automatic, try starting in neutral instead of park.

You might try opening the hood, providing you can keep an eye on the vehicle while the hood is up. This will allow your engine to cool down a little more quickly.

I like the spade connector idea (cheap and simple). I had something like that happen on my oil pressure sending cable once on the highway…talk about heart attack!!! I’ll check that out for sure. It’s also been suggested that maybe the starter relay might be the culprit. I guess I can use the click and clack approach and hold a new one in my hand while I look for something that matches.

Good stuff… thanks for the ideas, not sure when I can confirm the fix but hot weather is here to stay for a while so I’ll try

The starter relay, also known as the solenoid is attached to the starter motor. It is an integral part of the starter, it is where the wires are attached. You normally just replace the whole starter when one of these goes bad.

I could not rule out the solenoid completely, but the condition you have is not a common failure mode for it. It would be very rare for this to be the culprit.

I’ve heard that on others but I notice in a search there is a little plug in starter relay. bout $11. … we’ll today I pulled off the spade connector and the rubber cover that should be over it was decayed off. The spade was pretty corroded so just for grins I wire brushed it and tightened it with some plyers then re-connected it. Looking at my engine it looks like the starter is pretty far from the exhaust so I’m not so sure that is an issue for this car. Also, it looked like the starter would not be as difficult as others I’ve replaced so I suppose I could tackle that if necessary.