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Possibly Overheating?


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Hey guys. Yesterday I was driving a good bit on the interstate and my truck got so hot that it melted the Map sensor line where it curved to go into the throttle body (luckily had enough line in my toolbox to make another. ) I think it was laying on the intake manifold heat shield and thats why it melted it. Before I found the map line, I thought it was overheating because I don't have a temp gauge and it's always really warm in the engine compartment. I opened the pressure bottle and well... it had a lot of pressure in there which I figured was normal. But my antifreeze/water was really really dirty and seemed low? My electric fan also never turns on. After driving my truck for about 30 minutes I can't touch the valve cover for more than a couple seconds without it burning me. I have a laser temp gauge sitting around that my dad used for work and it tests up to 1000 degrees. Where could I point the laser to test how hot the engine is running? And how can I change the antifreeze/water to make sure it has what it needs in there? And for the fan not working, how is that fixable? Also please note I haven't changed the thermostat.


Thanks.

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I will try to answer in order

 

1)    Unless you have an established benchmark for temperature the lazer readings will not help…but that being said take a reading on the side of the block….the water pump…..the rad…write them down and report back.

 

2)    The rad has a petcock drain on the bottom. Put a container under it..... drain the fluid…..fill with clear water….run for 10 minutes…let it cool down….drain it again. Top up with correct anti- freeze mix.(Up here we use minimum 50/50 but from your location you could get away with less)

 

3)    Pull the plug on the electric fan….test that the fan is working by running a hot lead right from the battery. If it works most install a relay under the hood running direct power (fused) from the battery…through the relay. The relay is run back to a cab mounted switch that is hooked into the fuse box accessory out-put

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If your truck isn't overheating, the auxiliary fan would not turn on.

 

That coolant pressure bottle is like an extension of your radiator. Just as you should not remove the radiator cap when the system is hot, you also do NOT remove that cap when the system is hot. When the system is cold, the coolant level in the plastic bottle should be halfway -- NOT completely full. It's a sealed system, and the coolant needs some space to expand.

 

Aim your thermometer at the left rear corner of the head. Temperature should be between 200 and 215 degrees F.

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Time for an update. I got some more vacuum line just so I could run it away from anything that would be to hot... and well, this time the line melted itself in half, at 110 degrees! I just had the truck idling for 30 minutes and revved it up a few times and it got nice and warm. I checked temp and it was 150 where Eagle told me to point the laser. it was 160 on the front of the head, and I had 150 on the intake manifold heat shield. I figure its not running hot... but what can I do about my MAP sensor line? It wasnt touching anything and melted straight in half! I even made sure to check and it was Dorman brand Vacu-lite heat resistant emissions line. I would prefer it not burn itself in half while I was going down the road, so what are my options? 

Thanks.

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I would prefer it not burn itself in half while I was going down the road, so what are my options?

Back in the days when all cars had idiot lights and I routinely installed mechanical oil pressure gauges, the gauges usually came with plastic tubing. I scrapped that and used copper.

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Wow I never thought about that... But will 1/8" copper bend how I need it to without crimping itself? I'm also considering putting in hood vents soon to help with the heat under the hood, what are the good options of hood vents and are there any sensors that need to be watched for to make sure rain won't ruin them?

Thanks

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I found some 1/8" Aluminum tubing. But the inner diameter seems to be about half the size of the emission lines inner diameter. Will the truck still run good with a smaller inner diameter line? I had read something about how a bigger line would make the engine take longer to respond because airflow would take longer to pressurize. I would just like to make sure this line will work okay before I fit it in there with a gasket maker.

 

Thanks.

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It wasn't the original line. I had to swap to some cheap emissions line from oreillys. The first time it melted it was some decently strong tubing BUT It was laying on the intake manifolds heat shield which I didn't think was actually supposed to be that hot. I've checked all temps and none got higher than overheating temps. At all. The most recent line that melted was RIDICULOUSLY cheap. As in you could see through the walls of the tubing. I got some line from a junkyard (checked for leaks, none appeared.) and it seems to be working good, except I'm having some miniature backfires and a kinda rough idle. 

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I replaced most all of my vacuum lines with 3/16" brakeline ... cheap, easily bent as required ... and doesn't melt ... fits the rubber connectors elbows tighter than the stock plastic as well.

Older picture ... but it's the green lines for MAP and FPR in this one.

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It's kinda thick. I would have a little bit more air flow through it than with the vacuum lines ive used. I measure the OD with a caliper and it's exactly 3/16". I'm probably going to force it on if this new line I got melts. So far so good though :thumbsup:

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