Please Help - Truck won't start when hot!

I do hope I wouldn't be a bother to you all but I actually thought ask questions about my issues on here with high hopes that you all might be able to give me one or three pieces of advise.

My problem is this, I drive a 1989 peterbilt 377 with cummins N14 engine. She starts normally but if I put it off after driving a while, it won't start back immediately unless I allow it to cool for about 30 minutes. Big pain that is!!

I have changed the kick starter and 4 batteries with no difference, she still does same thing, it won't start when hot until I allow it to cool.

Any advice will be highly appreciated as I'm totally lost on this one.

Many thanks in for your replies.

 

Many thanks for your suggestion. Can I ask please, where is the relay switch located? Also by "a short in my switch", which switch are you referring to? Sometimes when its hot and I try to start it before it cools down, the battery drags like they're weak and I end up still having to leave it to cool.

 

Many thanks. I haven't noticed a temp switch on her. If there's one, it should be located on the dash, right? What's the function if I may ask? I'll give it a check in the morning. Cheers.

 

Hi and thanks Philip. The starter is brand new, not up to 3 weeks old. Its the second starter I've put in the space of two months as I thought I had been sold a factory faulty starter. This means that I've had three different starter and problems still persists. It starts fine in the morning but after some driving and you put it off say in traffic, it wouldn't come back on until it cools for about 30 minutes. If I try to start it before it cools off, it drags like the batteries are weak and wouldn't roll the engine. When I allow it to cool, it fires away like nothing was ever wrong. And my batteries are new, just four months old. Thanks for your input.

Abim.