mrsunset
New LVC Member
Hi all. I want to thank each and every poster for the significant amount of information available for folks to read through and research their problems. I have been using this forum to solve my Coil on Plug engine stumbling problem (2 COP's soaking in oil), and most recently, overheating.
I have a 2001 LS 3.9 I purchased a year ago with 107K miles. I started with the usual symptoms, overheating, coolant on the ground under driver side wheel well. Originally replaced the thermostat, finding my Napa replacement coiincidentally matched the one I pulled out, but I took the time to make sure the air bypass plug was oriented at the top. More time and continued problems. Suspected maybe a blown head gasket, but the water vapor coming out the tailpipe wasn't really more than most of the other cars on he road. I ruled that out. Bled the system several times. During the last session, the heater stopped blowing hot air. Now I started thinking my DCCV valve or AUX pump may also be bad. So, as a first step, finally ordered the Dorman coolant tank for ~$60 from Amazon. Did the repair last weekend and found the stock tank, yellowed with age, with several vertical cracks clear through, and lots of other cracks. Bled the system and took the car for a drive with the heater on full blast, but no hot air. At least until about 45 minutes into the drive, then it started getting hot. Back in the driveway found the coolant level needed topping off. I figure the heater must have been air locked and finally pushed the fluid through, causing the fluid drop. Since the repair, I haven't had a problem yet with temperature or coolant on the ground. Heater is working fine so far. Will be watching the coolant level to see if there still may be some leaking elsewhere.
As to the coolant on the ground as a typical indicator, when the system pressure rises (up to the 16 psi cap check valve pressure), it forces the coolant out the cracks which are under the liquid level. It doesn't take a lot of coolant loss to leave the coolant sensor high and dry, which leads to quickly showing overtemp even from a cold start. When we talk of the leaks in the coolant system, it isn't that air is leaking in, but that coolant under pressure is being forced out. If enough coolant gets expelled, the air backfilling from the coolant reserve tank can make its way back into the system and temp sensor.
Although the Dorman tank is thinner, my hope is that it is newer, better plastic than the stock, thick, yellowed tank that is failing for so many of us. At least it is an inexpensive fix.
I was really preparing to have to tackle the DCCV, but that does not look like a very enjoyable exercise. Luckily it looks like I dodged that problem for now.
Thanks again to everyone that posts, leaving information to scour through.
Maybe a thread on how to most effectively search the vast knowledge here would be good, since I use the forum search tool, and as many others have stated, it is not very good and we miss a lot of the older posts with valid information. Newbies are always getting slammed for starting new threads and not researching better, but there really should be a sticky on "how to most effectively search the forums for your specific issue" using Google or what have you.
-Mr Sunset
I have a 2001 LS 3.9 I purchased a year ago with 107K miles. I started with the usual symptoms, overheating, coolant on the ground under driver side wheel well. Originally replaced the thermostat, finding my Napa replacement coiincidentally matched the one I pulled out, but I took the time to make sure the air bypass plug was oriented at the top. More time and continued problems. Suspected maybe a blown head gasket, but the water vapor coming out the tailpipe wasn't really more than most of the other cars on he road. I ruled that out. Bled the system several times. During the last session, the heater stopped blowing hot air. Now I started thinking my DCCV valve or AUX pump may also be bad. So, as a first step, finally ordered the Dorman coolant tank for ~$60 from Amazon. Did the repair last weekend and found the stock tank, yellowed with age, with several vertical cracks clear through, and lots of other cracks. Bled the system and took the car for a drive with the heater on full blast, but no hot air. At least until about 45 minutes into the drive, then it started getting hot. Back in the driveway found the coolant level needed topping off. I figure the heater must have been air locked and finally pushed the fluid through, causing the fluid drop. Since the repair, I haven't had a problem yet with temperature or coolant on the ground. Heater is working fine so far. Will be watching the coolant level to see if there still may be some leaking elsewhere.
As to the coolant on the ground as a typical indicator, when the system pressure rises (up to the 16 psi cap check valve pressure), it forces the coolant out the cracks which are under the liquid level. It doesn't take a lot of coolant loss to leave the coolant sensor high and dry, which leads to quickly showing overtemp even from a cold start. When we talk of the leaks in the coolant system, it isn't that air is leaking in, but that coolant under pressure is being forced out. If enough coolant gets expelled, the air backfilling from the coolant reserve tank can make its way back into the system and temp sensor.
Although the Dorman tank is thinner, my hope is that it is newer, better plastic than the stock, thick, yellowed tank that is failing for so many of us. At least it is an inexpensive fix.
I was really preparing to have to tackle the DCCV, but that does not look like a very enjoyable exercise. Luckily it looks like I dodged that problem for now.
Thanks again to everyone that posts, leaving information to scour through.
Maybe a thread on how to most effectively search the vast knowledge here would be good, since I use the forum search tool, and as many others have stated, it is not very good and we miss a lot of the older posts with valid information. Newbies are always getting slammed for starting new threads and not researching better, but there really should be a sticky on "how to most effectively search the forums for your specific issue" using Google or what have you.
-Mr Sunset