I am stumped ---- Coolant Leak

racertracer · **Posted:** Fri Aug 12, 2011 9:00 pm

I am once again dealing with a glowing low coolant light on my dash.

I am stumped because I cannot find the leak.

1. The temperature guage remains constant, positioned to the left of the center mark.
2. The coolant bottle empties coolant into the reservoir during a long drive on freeway causing the the coolant low level light to come on.
3. I used a pressure tester to see if the pressure dropped over night and it did. It went from 16lbs to 13 lbs. I then tested it again by bringing the pressure up to 16lbs and it didn’t drop, it remained fixed.

Have any of you encountered this issue? Could you shed light as to what maybe happening?
Tomorrow, I pick up a combustion leak detector kit from the auto parts store and I’ll report back.

Any ideas?

mdalien · **Joined:** Tue Jun 22, 2010 10:22 pm **Posts:** 41

On mine it was the water pump slowly leaking.
Since they buried it you can't see the weep hole or a puddle unless you have a large leak.

I H Man · **Joined:** Mon Jun 06, 2011 11:00 pm **Posts:** 2

When you first start it in the morning do it miss on one cylinder for a second or two then clear up and run fine after that. Mine did finally pulled the injectors after it wouldn't crank over after stitting a week or two and #3 cyl was filling with coolant. pulled head and had pressure check and head is cracked or bad casting in the the outside intake runner of the head,blew water everywhere. And yes it is a job to pull the head. Currently looking for an engine because #3 liner is damaged.

racertracer · **Posted:** Sat Aug 13, 2011 2:55 am

I H Man wrote:

When you first start it in the morning do it miss on one cylinder for a second or two then clear up and run fine after that. Mine did finally pulled the injectors after it wouldn't crank over after stitting a week or two and #3 cyl was filling with coolant. pulled head and had pressure check and head is cracked or bad casting in the the outside intake runner of the head,blew water everywhere. And yes it is a job to pull the head. Currently looking for an engine because #3 liner is damaged.

It cranks over fine and drives great, it mostly happens after a long hot drive coming off the ramp and then to a stop.

papaindigo · **Posted:** Sat Aug 13, 2011 8:07 am

Your #2 comment makes me wonder if you have a bad radiator cap (on the CRD the cap on the plastic reservoir) that's bleeding pressure too early and allowing too much coolant to flow into the overflow side of the tank on a hot engine. I don't know if the cap can be checked but a new one is cheap enough to just purchase and put on to see what happens.

If the combustion leak kit doesn't show anything try adding the appropriate UV dye, parts store should have, to the coolant, drive a bit and then use a UV light, parts store again or Amazon, to look for the leak. This is good for detecting tiny leaks and ones where the fluid drips to a hot surface and immediately evaporates. Years ago on another vehicle this method found a really tiny leak at a lower radiator hose fitting that wasn't tight enough.

There has been at least one report of detecting a water pump leak by looking up at the front passenger side of the engine, with the skid off I suspect.

If you changed your tstat recently there has been 1 report of a leak due to a stripped lower rear bolt, the one that's impossible to see well or get too without a long 1/4" wobble extension.

EGR coolant pipes?

Joe Dirt · **Posted:** Sat Aug 13, 2011 8:18 am

I have had some success with stubborn leaks using fluorescent dye. Put it in the coolant and take your long drive. Even if all the coolant that leaked out evaporated the dye will stay there. It will show up as soon as you shine a black light on it. Napa sells the dye.

racertracer · **Posted:** Sat Aug 13, 2011 9:05 am

Thanks Pap I appreciate your advice.

papaindigo wrote:

Your #2 comment makes me wonder if you have a bad radiator cap (on the CRD the cap on the plastic reservoir) that's bleeding pressure too early and allowing too much coolant to flow into the overflow side of the tank on a hot engine. I don't know if the cap can be checked but a new one is cheap enough to just purchase and put on to see what happens.

I am on the second radiator cap now, and yes the first one did explode fluid out because it was old and weak.

papaindigo wrote:

If the combustion leak kit doesn't show anything try adding the appropriate UV dye, parts store should have, to the coolant, drive a bit and then use a UV light, parts store again or Amazon, to look for the leak. This is good for detecting tiny leaks and ones where the fluid drips to a hot surface and immediately evaporates. Years ago on another vehicle this method found a really tiny leak at a lower radiator hose fitting that wasn't tight enough.

I'll be checking into this too.

papaindigo wrote:

There has been at least one report of detecting a water pump leak by looking up at the front passenger side of the engine, with the skid off I suspect.

Tried to get the skid plate off last night to check for leaks at the water pump, but one of the bolts willnot come off, it is free spinning and I might have to snap it with a chisel to get it off.

papaindigo wrote:

If you changed your tstat recently there has been 1 report of a leak due to a stripped lower rear bolt, the one that's impossible to see well or get too without a long 1/4" wobble extension.

Yes, it was my post, my bolt stripped and leaked and I needed a heli-coil to fix it. I hope that the previous thermostat leak isn't the casue of the present leak or an expensive head gasket repair.

papaindigo wrote:

EGR coolant pipes?

These are the hoses and pipes that are under the egr valve..... I tighten the clamps on those the other night.

What puzzles me is this, I checked the system pressure the other night and it didn't hold up, it leaked.

But then I rechecked it and it held up fine.

flman · **Posted:** Sat Aug 13, 2011 9:09 am

racertracer wrote:

I am once again dealing with a glowing low coolant light on my dash.

Have any of you encountered this issue? Could you shed light as to what maybe happening?
Tomorrow, I pick up a combustion leak detector kit from the auto parts store and I’ll report back.

Any ideas?

That sucks, you are the only one that has ever mentioned a CRD issue like this?

racertracer · **Posted:** Sat Aug 13, 2011 9:27 am

It looks like that there is a lot of pressure being built up in the coolant bottle and pushing coolant into the reservoir.

Why would a coolant leak create such pressure, or is this pressure built up from a leaky head gasket?

Turbo Tim · **Posted:** Sat Aug 13, 2011 9:37 am

I have seen this on other vehicles too. I suspect it is the shaft seal on the water pump. Depending on where the seal stops, it leaks or it doesn't.
Possibly leaking when the engine is running and that is why you don't see it.

Do the dye and then check.

racertracer · **Posted:** Sat Aug 13, 2011 9:59 am

Turbo Tim wrote:

I have seen this on other vehicles too. I suspect it is the shaft seal on the water pump. Depending on where the seal stops, it leaks or it doesn't.
Possibly leaking when the engine is running and that is why you don't see it.

Do the dye and then check.

Will do.

DOC4444 · **Posted:** Sat Aug 13, 2011 2:32 pm

Here's a shurefire way of finding a slight headgasket leak that does not show up with a blokchek. Find someone with an exhaust emissions tester. Remove pressure cap and insert the probe in the header tank just above the coolant level. Rev to 2000 rpm. If the tester does not pickup any CO, your headgasket should be good. Hopefully, it is just your water pump.

BTW, didn't someone else find a coolant loss problem caused by a leak in their EGR cooler?

DOC

racertracer · **Posted:** Sat Aug 13, 2011 4:29 pm

OK...

1. I poured dye in the coolant bottle and drove around for about 20 minutes.
2. I then removed the skid plate and went around the engine compartment with a UV light but I couldn't see any leaks.
3. I drove to my local vehicle emissions inspection stations and the mechanic was kind enough to use the emiission probe in the bottle just above the coolant while I revved the motor to 2000 rpm, but he didn't get any indication that exhaust fumes were present... So no exhaust fumes in the coolant.

The mechanic thinks that the coolant could be escaping out of the exhaust side and vaporizing. What is your view?

How do I check for this scenario?

Note:
The coolant in the bottle continues to drop in volume after long drives, more so after reaching highway speeds of 60 MPH or above and during turbo spool. When the vehicle is at idle there is less loss of coolant or none at all.

The amount of coolant the vehicle loses after an hours drive on the highway, is approximately one cup of fluid - give or take.

The vehicle drives great, but I am getting ready for the worse.

DOC4444 · **Posted:** Sat Aug 13, 2011 5:32 pm

I don't see how combustion gases can escape through the head gasket into the coolant and not register on a CO meter unless it is not working. With your header tank "pressurizing", it is hard to imagine where the pressure is coming from other than combustion gas.

Have you tried putting the overflow tube into some type of catch bottle? If combustion pressure is getting into the cooling system, it would easily overcome the capacity of even a brand new rad cap and blow coolant out the overflow.

DOC

racertracer · **Posted:** Sat Aug 13, 2011 5:47 pm

DOC4444 wrote:

I don't see how combustion gases can escape through the head gasket into the coolant and not register on a CO meter unless it is not working..

I agree. The mechanic did say that the testing machine he was using was probably made to read gasoline engines and not diesels.... he wasn't sure.
so I think I am back to square one on this test.

DOC4444 wrote:

With your header tank "pressurizing", it is hard to imagine where the pressure is coming from other than combustion gas.

I agree.

DOC4444 wrote:

If combustion pressure is getting into the cooling system, it would easily overcome the capacity of even a brand new rad cap and blow coolant out the overflow.

It does.... after a long hot drive especially after the turbo spools.

But on other times it doesn't.

papaindigo · **Posted:** Sat Aug 13, 2011 9:54 pm

For what it's worth 20 minutes driving is way too little time produce enough leaked dye to find a small leak with UV. My, I'll admit, 1 experience with a small leak required like 250 miles to locate a small but constant hose fitting leak of ca. 1 cup per 250 miles.

Your header (plastic tank on the firewall) tank routinely pressurizes as the coolant heats up. It's possible that it's going over pressure for a variety of reasons (engine temp/radiator cap or combustion leak are both possible). If there is no evidence of coolant in the oil or combustion gas in the coolant then I'd be looking for why the coolant is leaking somewhere including going over pressure in the tank.

racertracer · **Posted:** Sat Aug 13, 2011 10:17 pm

Pap,

Thanks for the advice.

I will keep driving it and looking for leaks.

I will be retesting the system using one of these:

http://www.uview.com/ProductDetail.php? ... ber=560000 I ordered it today and should arrive in a few days.

Keeping the faith.

Racer

DOC4444 · **Posted:** Sat Aug 13, 2011 10:33 pm

I'm confused. You stated slightly earlier in response to my post that you ARE blowing coolant out the overflow tube with a brand new radiatior cap. If so, why are you looking for leaks? You know where the coolant is leaving the system. The only issue is precisely where the pressure is coming from (i.e. blown headgasket, cracked head, ???, etc.).

DOC

racertracer · **Posted:** Sat Aug 13, 2011 10:57 pm

Delving into false hope.

Hoping that the obvious isn't so, while I continue to search for an easy fix and maybe find a flaw in the steps I've taken so far while praying for a miracle.

Stumped because it doesn't happen all the time.

DOC4444 · **Posted:** Sat Aug 13, 2011 11:59 pm

Start reading about K-Seal. It worked wonders with our Kubota diesel tractor.

DOC

I am stumped ---- Coolant Leak

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