Mystified
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Joined: Nov 2008
Posts: 54
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From: Wyoming
Mystified
I'm stumped...
The truck in question is a 2001 4x4 5.2L auto with 97k on the ticker.
A few months back, my truck began starting rough when it was cold in the morning. I did a little research and found out that the coolant temp sensor was the likely culprit. I took it out and tested it, and sure enough it was bad. I replaced it and then the high idle started coming on like it should on a cold start and the problem went away...
I started smelling antifreeze, not so much in the cab but mostly under the hood (the heater core is new). I looked around for awhile and discovered that it looked like my thermostat gasket was seeping a little bit. Not much of a leak, but enough to make an odor I figured. I wanted a hotter heater anyway, so I went to a 190 thermo while I was at it.
Now the truck is doing the rough cold start bit again. There is still an antifreeze odor after the truck has been running for awhile and is up to full op temp. The hoses are all brand new. The heater core is new. The water pump is new. There is no antifreeze leaking out from anywhere that I can spot with the eye. Wherever it's going, it's a small leak, because the coolant level takes days of driving to drop enough to even be able to tell.
Oil is going somewhere as well. It uses about two quarts between 3000 mile oil changes. There's no smoke from the tail pipe, not even when I get on the throttle hard. I can park it for a few days at a time and there won't be so much as a drop on the pavement.
It's just a lowly 318 with factory gears pushing 35" tires around, so it's obviously no powerhouse. The power output seems "moody" though. Sometimes I'll put my foot into it to pass or merge onto the interstate or whatever, and it seems to pull nice and strong. Other times it can't seem to get out of it's own way. It always seems to run perfectly. Smooth running. Smooth idle (once it warms up for about a min).
I'm lost. Any ideas??
The truck in question is a 2001 4x4 5.2L auto with 97k on the ticker.
A few months back, my truck began starting rough when it was cold in the morning. I did a little research and found out that the coolant temp sensor was the likely culprit. I took it out and tested it, and sure enough it was bad. I replaced it and then the high idle started coming on like it should on a cold start and the problem went away...
I started smelling antifreeze, not so much in the cab but mostly under the hood (the heater core is new). I looked around for awhile and discovered that it looked like my thermostat gasket was seeping a little bit. Not much of a leak, but enough to make an odor I figured. I wanted a hotter heater anyway, so I went to a 190 thermo while I was at it.
Now the truck is doing the rough cold start bit again. There is still an antifreeze odor after the truck has been running for awhile and is up to full op temp. The hoses are all brand new. The heater core is new. The water pump is new. There is no antifreeze leaking out from anywhere that I can spot with the eye. Wherever it's going, it's a small leak, because the coolant level takes days of driving to drop enough to even be able to tell.
Oil is going somewhere as well. It uses about two quarts between 3000 mile oil changes. There's no smoke from the tail pipe, not even when I get on the throttle hard. I can park it for a few days at a time and there won't be so much as a drop on the pavement.
It's just a lowly 318 with factory gears pushing 35" tires around, so it's obviously no powerhouse. The power output seems "moody" though. Sometimes I'll put my foot into it to pass or merge onto the interstate or whatever, and it seems to pull nice and strong. Other times it can't seem to get out of it's own way. It always seems to run perfectly. Smooth running. Smooth idle (once it warms up for about a min).
I'm lost. Any ideas??
Amateur
Joined: Oct 2010
Posts: 48
Likes: 0
From: rangely, co
I dont think i can help with the coolant issue but the oil leak is most likely the plenum pan gasket. it is a common problem on these trucks, i just got done replaceing mine about 2 months ago. what you need to do is take the air cleaner housing off and open the throttle blades and look down it with a flashlight, if you see oil its the plenum gasket. I would get a hughes repair kit for it. http://www.hughesengines.com/Index/index.php
Amateur
Joined: Oct 2010
Posts: 48
Likes: 0
From: rangely, co
the plenum repair is pretty basic there is alot of info on this forum. the main thing i would recommend would be to do a complete tune up while your at it. I thought my truck ran fine, but i kept using oil, i found out about the plenum leak and fixed it plus did a tune up and it made a difference. If this is something your going to do yourself you may want to think about doing the keggar mod. here is the link https://dodgeforum.com/forum/2nd-gen...e-mod-diy.html
the coolant issue, if you can get your hands on a pressure tester then pressure test the system and seach for leaks plus pressure check the cap.
the coolant issue, if you can get your hands on a pressure tester then pressure test the system and seach for leaks plus pressure check the cap.
Grand Champion
Joined: Aug 2009
Posts: 5,971
Likes: 45
From: MAINE
have you checked your timing cover gasket? they tend to leak coolant alot.....
and yes oil consumption is the plenum.....have you checked out your plugs? bad plenum can oil soak the plugs and cause more issues.
Do a search and all question will be explained....
Plenum has been discussed 1,937,642,284,591,773 times here. So theres plenty of topics on it.
and yes oil consumption is the plenum.....have you checked out your plugs? bad plenum can oil soak the plugs and cause more issues.
Do a search and all question will be explained....
Plenum has been discussed 1,937,642,284,591,773 times here. So theres plenty of topics on it.
Administrator
Joined: Apr 2010
Posts: 87,434
Likes: 4,217
From: Clayton MI
Oil consumption could also be due to an aftermarket PCV valve..... Get one from the dealer. They actually have the correct flow rate.
I had trouble with the mystery coolant leak as well.... took a while for it to finally show up.. Was the drivers side freeze plug behind the engine mount. I couldn't find it until it actually started leaving a puddle in the driveway.
Timing cover is another really good one.
I had trouble with the mystery coolant leak as well.... took a while for it to finally show up.. Was the drivers side freeze plug behind the engine mount. I couldn't find it until it actually started leaving a puddle in the driveway.
Timing cover is another really good one.