No pressure in cooling system

[doylee4693]

Been loosing coolant, quite a bit actually. Brought to mechanic last week and he replaced radiator hose clamp and still loosing coolant.I just Pressure tested resevoir cap and it held pressure. Pressure tested the resevoir and it wont build any pressure at all. No visible signs of leaks. 03 with 130,000 miles. Any ideas?

 

[OR VietVet]

First: When you pressure test the cap it should pop off when the stamped pressure on the cap is reached and you go past that pressure and should not drop when is at the stamped pressure. Did it do that?

Second: Either you have a bad seal with the tester itself at the reservoir or there is likely a crack up toward the top at the reservoir bottle. You may also have a leak at the radiator at the very top part of it. I am assuming, since you did not say so, that the reservoir was at the full mark when tested. You may also have head gasket problems. Check the condition of the oil for a mix of coolant and oil. How long has this problem been happening? Did you look for the obvious signs of leakage? Bottom of water pump? Back of intake?

You have to remember that metal expands and contracts and it may not show pressure loss at cold or hot but does when it is at the other temp range while driving or parked. Clear as mud?

 

[doylee4693]

First: When you pressure test the cap it should pop off when the stamped pressure on the cap is reached and you go past that pressure and should not drop when is at the stamped pressure. Did it do that?

Second: Either you have a bad seal with the tester itself at the reservoir or there is likely a crack up toward the top at the reservoir bottle. You may also have a leak at the radiator at the very top part of it. I am assuming, since you did not say so, that the reservoir was at the full mark when tested. You may also have head gasket problems. Check the condition of the oil for a mix of coolant and oil. How long has this problem been happening? Did you look for the obvious signs of leakage? Bottom of water pump? Back of intake?

You have to remember that metal expands and contracts and it may not show pressure loss at cold or hot but does when it is at the other temp range while driving or parked. Clear as mud?

I pumped up the cap to the 15psi and held the pressure there for 10 mins. The bottom of the water pump feels dry and from what I can see, no drips. The problem occured 3 weeks ago and every week it goes under the fill line by about an inch with very light use, 50 miles or less a week. I didnt notice it until after my oil change 3 weeks ago, and the oil didn’t look bad but was pretty thin from condensation and how I drive it, which is only about 5-7 miles a day. If it is the head gasket, shouldn’t the expansion tank bubble from gasses upon start up with the cap removed?

 

[OR VietVet]

You have to look at the bottom of the water pump for the corrosive stain coolant leaves when it leaks. I have seen the stain but have never seen drops on the ground before. From what you can see, no drips? You mean what you could see on your hand when you said it feels dry or did you crawl under and look or use a mirror, like I used to. I did not want to get on the ground unless I had to.

The bubbles in the reservoir would be an extreme instance. Time for a compression test on all cylinders and maybe a cylinder leak down test. That can wait for a bit on the leak down test.

What does it look like at the back of the intake? Did you check all over under the engine for welch plugs/freeze plugs leaking?

Others will chime in.

 

[doylee4693]

No but im off to get a combustion leak detector now to see if it is indeed a head gasket. Im not sure about the intake and if im honest, im not mechanically inclined enough to know where to look. Gonna see if I cant get an inspection mirror while im out to get a better look at the water pump. It’s got the 862 heads, so I guess it could be the dreaded castech heads too.

 

[OR VietVet]

Two must haves if you are going to try and diagnose some items on your own rig. A flexible head mirror that has an extension arm and a mechanics stethoscope for listening for noises. Make sure you read the instructions on the combustion leak detector kit. If you get ANY coolant sucked back in the chemical during the process, it is no good at that point and you start over. Good luck and report what happens please.

 

[doylee4693]

Tested fine but I noticed this

 

[OR VietVet]

Taste it. Does it taste like anti-freeze. I mean, if you do taste it just a finger tip will do. But it is likely the water, by-product of the combustion process, that all tailpipes will drip out.

By the way, what "tested fine?"

 

[doylee4693]

I tested it with a block tester and no issues there! The water keeps dripping tho, exhaust doesnt smell “off”. Call me paranoid but I really dont wanna taste that LOL

 

[doylee4693]

Im collecting some of the fluid from the tailpipe. It does appear clear at least.