andrewbourdeaux
Registered User
Hey there. I'm new here and this is my first post.
I have a 1994 Ford E350 7.3L IDI, non turbo ambulance. After starting up, my heat begins warming up and as I am driving down the road, it will suddenly start blowing cold after maybe 20 minutes. It will blow cold for maybe 10 minutes, then immediately becomes hot again for 5-10 minutes, then cold and it's a back and forth cycle that goes on indefinitely. I have had this problem since I bought the ambulance three years ago. Coolant is at the cold fill line when the engine is cold and there are no leaks.
Another thing to note that could be related is that I can roar down the highway at high RPMs (not sure exactly what because there is no tach) or hammer it up a 6-8% grade here in Colorado and my engine temperature gauge will not exceed the letter 'O'. Often times it doesn't even exceed 'N'.
As for the heat going cold issue, when it switches back and forth, there is a different sound coming from the air ducts. You can hear when it switches. I've also tried running heat on A/C mode as well as Vent mode.
Thank you for any advice you have!
Andrew
I have a 1994 Ford E350 7.3L IDI, non turbo ambulance. After starting up, my heat begins warming up and as I am driving down the road, it will suddenly start blowing cold after maybe 20 minutes. It will blow cold for maybe 10 minutes, then immediately becomes hot again for 5-10 minutes, then cold and it's a back and forth cycle that goes on indefinitely. I have had this problem since I bought the ambulance three years ago. Coolant is at the cold fill line when the engine is cold and there are no leaks.
Another thing to note that could be related is that I can roar down the highway at high RPMs (not sure exactly what because there is no tach) or hammer it up a 6-8% grade here in Colorado and my engine temperature gauge will not exceed the letter 'O'. Often times it doesn't even exceed 'N'.
As for the heat going cold issue, when it switches back and forth, there is a different sound coming from the air ducts. You can hear when it switches. I've also tried running heat on A/C mode as well as Vent mode.
Thank you for any advice you have!
Andrew
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