What can cause a temporary no-start??? Dealer hasn't found it yet.

[swilson143]

A few months ago my truck went to the dealer overheating and with an unexplained no-start problem. They did the head gaskets which seems to have corrected the temp issue, but they couldn't explain the no-start. Now this weekend the temporary no-start problem came back.

The circumstances couldn't be different except that both times I was towing my Toy Hauler. The first occasion I was pulling a tough grade, engine temp suddenly spiked at the summit, made it over the top just fine and ran normal all the way down the backside of the mountain. Then as the road leveled out I gave it some throttle to maintain my speed and it did not respond... just continued to slow until stopped. No check engine light or any other indicators on dash. Once stopped engine cranked over strong but wouldn't start. After sitting more then 20 min it just started up like normal and ran fine the whole way home... luckily before the tow truck arrived.

This weekend I had just towed 3+ hours, pulled into my usual fuel station just before arriving home, and after the fill up it would crank strong but not start. Again no check engine light. A good samaritan gave me a tug to get me away from the pumps so I wasn't tying up the entire lane and then after letting it sit for 15 min it started up like normal.

Any ideas?

[Abrannan19]

could be the HPOP fitting leaking if it hadn't been upgraded with the 1 piece unit when the gaskets were replaced. But that wouldn't explain the temperature spike.

[swilson143]

I was under the impression the temp spike was caused by the HG leaking. They didn't mention anything to me about HPOP parts when the did the HG job. What does the new part do?... or what was wrong with the original design?

[Abrannan19]

the old design of the HPOP STC fitting was a two piece design that was know to leak oil, causing no start issues. The new design is a 1 piece fitting. The temp spikes could be a restricted oil cooler, or EGR cooler, when the temp spiked, did you hear the fan come on?

[swilson143]

That trip was the second trip where the temp spiked. The dealer did the oil cooler after the first... HGs after the one I mentioned in this thread. After the HGs I haven't seen the temp gauge move. Fan had been on for awhile since it was a long hill climb.

What does STC stand for? And thanks for all the info!

[Abrannan19]

Snap To Connect Fitting. If the fan is on, the oil or coolant temps were high, 230* or over, if towing heavy loads, I would highly recommend getting some type of gauge that will read Oil temps and coolant temps, it will save you alot of headaches in the long run, also it will let you know what the exact temps are and when to let off when pulling a steep grade. Some people think they should be able to floor it all the way up an 11* hill for 4 miles or whatever and have no issues, unfortunately this just isn't the case.

[rjwareagle]

what is the danger zone for coolant temps?

[Abrannan19]

I wont say an exact number, because I don't want to be liable. I don't like to see mine get over 230*

[rjwareagle]

sorry to hijack. good i have never seen over 200. reached 200 in the mountains once. usually runs around 173-180. thanks

[kingranch89]

mine did the same thing when my HPOP was leaking