Low Coolant

mikey1273 · **Posted:** Thu Nov 01, 2012 6:34 am

I'm getting the message again. last time I had to add some was about a year ago when the weather changed to colder like it is now. Then it wasn't much that i did add maybe a cup or so to get it in working range again. I have not seen any leaks on the ground or anything and I'm guessing it would be hard to find such a small leak. any place I should look first?

papaindigo · **Posted:** Thu Nov 01, 2012 7:24 am

Add UV dye, get UV light, drive a few days, in shade look for leak with UV light.

dirtmover · **Posted:** Thu Nov 01, 2012 7:58 am

Mine has shown low on a couple of occasions when it's been very cold while visual inspection revealed that the reservoir was full.

MtnClimber · **Posted:** Thu Nov 01, 2012 10:12 am

Mine started to do the same thing about two months ago when she was cold (i.e sitting overnight or all day at work). No signs of any leaks, but I did notice that the level in the coolant reservoir was just below the cold fill line so I added maybe 8 - 12 oz of water and the problem has not come back.

mikey1273 · **Posted:** Thu Nov 01, 2012 10:31 am

adding 8-12 oz is what I did the last time it was just below the low fill line when I checked it. its there again a year later. It also only gives me the low cool in the morning after it has sat all night

I might have to see where to find this UV dye. then I would need a black light too which I don't have..... maybe I can find some hippy to lend me one LOL!

It has to be a very small leak for only that amount to get away. like a heater hose or EGR cooler line gettin ready to go. I did an oil analysis in the spring and no trace of coolant showed up there at the time.

papaindigo · **Posted:** Thu Nov 01, 2012 11:25 am

Any good parts store with have the UV dye (make sure it's compatable with HOAT coolant) and you can get the UV/black light flashlight cheap from Amazon (you might could buy just a bulb for a regular flashlight)

bugnout · **Posted:** Thu Nov 01, 2012 12:46 pm

Is there any coolant in the overflow part of the resevour? Since I changed the coolant about 10 months ago, I have had low coolant indications often. Almost always its due to the overflow not getting sucked back into the resevour when it cools. Not sure why, I've changed the cap, and checked for leaks, can't find anything wrong.

I can go for a month without having a problem, then for no reason I can decern, I'll have to drain the overflow and pour it back in every other day, then it goes away and I get another month with everything working normally.

papaindigo · **Posted:** Thu Nov 01, 2012 1:01 pm

Just a thought but you might want to check the "degas" hose from the tstat to the tank. That hose runs from the small right angle plastic outlet on the tstat to the tank and the hose is rather small and pliable. I could certainly see that hose getting kinked so that it would occasionally pass hot coolant under pressure but not pull back coolant as the system cools down.

bugnout · **Posted:** Thu Nov 01, 2012 4:43 pm

Thank you sir...I will check that.

Dave01 · **Posted:** Thu Nov 01, 2012 7:51 pm

I'll check that hose as well. I've been losing coolant and having to add about every week, maybe 8-10 oz. each time. I did see the overflow being full, and can't find any leaks. I've been worried I might have a blown gasket, are there any common problems with intake or exhaust that would eat coolant? No white smoke at all. I'm getting worried with the amount I'm losing regularly, I do put a lot of miles on it.

papaindigo · **Posted:** Fri Nov 02, 2012 9:03 am

The UV method works well for external leaks even very small ones which can be invisible and cause a surprising amount of coolant loss. In checking via the UV method don't forget the EGR cooler low down on the driver's side of the block.

For a head gasket leak see racertracer's test method at viewtopic.php?f=5&t=72329

Dave01 · **Posted:** Fri Dec 28, 2012 1:58 am

We found one very small coolant leak at a hose connection, fixed it. I'm still losing coolant and seeing it in the overflow tank. It's been running cool, and when warming up the heater would throw some heat, then go cold, then at operating temp would warm up again and stay warm. My mpg have been lower than last year.

I installed a Stant 13519 inline stat today, with 3/32 hole drilled. As expected it warmed up quickly, heater threw much more heat, I'll see what mileage looks like over the next few weeks. I still see coolant in the overflow. I checked that return hose, and it's not kinked and not blocked from what I could see.

One comment - when I pulled the hose to install the inline stat, there was no coolant in it. I expected a full hose and losing a bit, but nothing there. Is that a clue to anything?

LMWatBullRun · **Posted:** Fri Dec 28, 2012 8:33 am

bugnout wrote:

Is there any coolant in the overflow part of the resevour? Since I changed the coolant about 10 months ago, I have had low coolant indications often. Almost always its due to the overflow not getting sucked back into the resevour when it cools. Not sure why, I've changed the cap, and checked for leaks, can't find anything wrong.

I can go for a month without having a problem, then for no reason I can decern, I'll have to drain the overflow and pour it back in every other day, then it goes away and I get another month with everything working normally.

THis is symptomatic of HG issues. DO a vacuum test on the cooling system, and if it won't hold vac, HG.

LMWatBullRun · **Posted:** Fri Dec 28, 2012 8:37 am

Dave01 wrote:

We found one very small coolant leak at a hose connection, fixed it. I'm still losing coolant and seeing it in the overflow tank. It's been running cool, and when warming up the heater would throw some heat, then go cold, then at operating temp would warm up again and stay warm. My mpg have been lower than last year.

I installed a Stant 13519 inline stat today, with 3/32 hole drilled. As expected it warmed up quickly, heater threw much more heat, I'll see what mileage looks like over the next few weeks. I still see coolant in the overflow. I checked that return hose, and it's not kinked and not blocked from what I could see.

One comment - when I pulled the hose to install the inline stat, there was no coolant in it. I expected a full hose and losing a bit, but nothing there. Is that a clue to anything?

Yes, this combined with the presence of coolant in the overflow tank are strongly indicative of HG issues. WIth a leaking HG, the coolant is forced out under pressure from the cylinder, and with a leaking HG, there is no vacuum to pull the coolant back in when things cool down. Do RT's test, and then, if that shows positive, do a vacuum test on the cooling system to confirm.

Dave01 · **Posted:** Fri Dec 28, 2012 8:53 am

I did RT's test yesterday, 2nd time I've done it, didn't hear any air from the cap. Also, when I've let the system cool down and pulled the cap, there is still some vacuum there. So, though I agree the symptoms look like a bad HG, but not seeing the system pressure to indicate it.

I'll do the vacuum test and leak test again and see if I can figure this out. It runs fine, holds temp fine now with the inline stat, hard to figure out.

racertracer · **Posted:** Fri Dec 28, 2012 8:58 am

LMWatBullRun wrote:

Dave01 wrote:

We found one very small coolant leak at a hose connection, fixed it. I'm still losing coolant and seeing it in the overflow tank. It's been running cool, and when warming up the heater would throw some heat, then go cold, then at operating temp would warm up again and stay warm. My mpg have been lower than last year.

I installed a Stant 13519 inline stat today, with 3/32 hole drilled. As expected it warmed up quickly, heater threw much more heat, I'll see what mileage looks like over the next few weeks. I still see coolant in the overflow. I checked that return hose, and it's not kinked and not blocked from what I could see.

One comment - when I pulled the hose to install the inline stat, there was no coolant in it. I expected a full hose and losing a bit, but nothing there. Is that a clue to anything?

Yes, this combined with the presence of coolant in the overflow tank are strongly indicative of HG issues. WIth a leaking HG, the coolant is forced out under pressure from the cylinder, and with a leaking HG, there is no vacuum to pull the coolant back in when things cool down. Do RT's test, and then, if that shows positive, do a vacuum test on the cooling system to confirm.

Yes, what LMW said. Also make sure you're not driving it with coolant in the oil because it could lead to even more engine problems real quick.

Did the coolant issue begin to happen after the inline thermostat install or before?

Dave01 · **Posted:** Fri Dec 28, 2012 9:40 am

racertracer wrote:

Yes, what LMW said. Also make sure you're not driving it with coolant in the oil because it could lead to even more engine problems real quick.

Did the coolant issue begin to happen after the inline thermostat install or before?

No, just installed the stat yesterday, have had the coolant loss issue for maybe 3 months now.

Last oil change oil looked fine. I've got a Fumoto valve so I'll drain a bit of oil and take a closer look, I think I'm due for a change in the next few miles anyway. Would UOA show presence of coolant?

kissfan79 · **Posted:** Fri Dec 28, 2012 10:23 am

The ones I get from Blackstone Labs do. They show it at the bottom and it is listed as a %.

Jim

yakers · **Posted:** Sat Dec 29, 2012 1:20 am

An oil analysis or ultraviolet dye is a good way to go. Blackstone identified coolant in my oil as did the dye later despite two Jeep dealers saying I did not have a leak based on presure testing and sniffing the coolant resevior for exhaust.

Dave01 · **Posted:** Sat Dec 29, 2012 1:26 am

yakers wrote:

An oil analysis or ultraviolet dye is a good way to go. Blackstone identified coolant in my oil as did the dye later despite two Jeep dealers saying I did not have a leak based on presure testing and sniffing the coolant resevior for exhaust.

Once you found out, did you replace the head gasket?

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