ARPs not take, or a different leak?

Mountainman · **Posted:** Sun Jul 05, 2015 12:02 pm

This CRD I've been fixing on was slowly consuming fluid. I had to do timing belt anyhow, so I installed ARPs one by one and put in new rockers.

So, my two questions are, after how many warm ups will the fluid quit dropping (I thought it was just a few?) and how much fluid will you lose from a radiator cap that has some small cracks in the rubber seal?

The consumption hasn't changed, so I just put on a new radiator cap, and I keep hunting but can't seem to find a leak anywhere else, yet....

I sure hope that I don't have to pull the head next, because I've been running it for a few weeks now, and I just topped the fluid off for about the third time.

Thanks for reading :JEEPIN:

Mountainman · **Posted:** Sun Jul 05, 2015 12:04 pm

Oh, I'm going to check for bubbles this morning. Wish me luck!

I also checked for pressure and found none, but that's when I noticed the bad cap...
Oh! and there's a tiny bit of rust at the bottom of the block heater, but I can seem to get any moisture off of it when it's running hot. Maybe it leaks under a highway load?

papaindigo · **Posted:** Sun Jul 05, 2015 12:19 pm

Based on a few times of draining and filling a CRD cooling system I fill the coolant tank to ca. 1" or a bit less above the mid line and after about 4-5 drive cycles (up to operating temp and back to cold) the level drops to about the mid line and stays there.

How fast is your coolant level dropping?

There are a host of places for "invisible" external coolant leaks that can result in fairly significant coolant loss. By invisible I mean ones that do not result in coolant on the ground or some such. For example I had a fairly significant rate of coolant loss decades ago on a new vehicle that was traced to the lower radiator hose clamp; no visible drip as coolant evaporated as soon as it came out.

My standard recommendation is get so coolant UV dye; add to system; drive for a week or so; park in shade/night/garage and look for leak with UV light. Don't forget hard to see spots such as EGR cooler and oil cooler.

Mountainman · **Posted:** Sun Jul 05, 2015 12:27 pm

Many thanks, I guess I'll be going your UV route if there are no bubbles or pressure after 30 seconds.

It lost about 1/3" in reservoir in 250 hot, steep grade mountain miles. Well, most of those were on a flat highway at 104 F, but there were about a dozen serious grades that I went over. It definitely looks like it might seep at the block heater under serious loads, maybe that plus the radiator cap caused it. It was a very slow leak before I installed the studs. I think it may be going faster with heat and major mountain grades. :banghead:

flash7210 · **Posted:** Sun Jul 05, 2015 12:38 pm

Pressure test the cooling system.
Pump it up to but dont exceed 16 psi.
Let it sit for 30min to 1 hour.
Come back and check for drips on the ground and check the level in the coolant tank.

Mountainman · **Posted:** Sun Jul 05, 2015 1:01 pm

Thanks Flash, do you have any advice on what's a good cheap kit for the testing? Is there an adapter for this in my Miller tool set? :5SHOTS:

papaindigo · **Posted:** Sun Jul 05, 2015 1:26 pm

Don't forget coolant flows thru the heater core all the time and any drip from that will be mixed with the normal AC drip when the AC is operating. Check AC drip to see if it tastes sweet, if so heater core is leaking.

Pressure test might work but did not find that tiny lower radiator hose leak I mentioned earlier.

Mountainman · **Posted:** Sun Jul 05, 2015 1:33 pm

Thanks again Papaindigo, if the heater core is leaking I'm driving it off a cliff and doing a claim...

papaindigo · **Posted:** Sun Jul 05, 2015 1:54 pm

Well heater cores can be fixed although now days it's a pain in the booty. There was a time when getting to a heater core was as simple as popping like 4-6 clips on the heater box cover in the cab, undoing the heater hoses, and yanking the core out - elapsed time say 30 minutes. If mine was leaking I'd just cut it out of the coolant circuit by looping the hoses and live without heat but I don't suppose that's a viable option in Idaho.

Mountainman · **Posted:** Sun Jul 05, 2015 2:31 pm

papaindigo wrote:

Well heater cores can be fixed although now days it's a pain in the booty. There was a time when getting to a heater core was as simple as popping like 4-6 clips on the heater box cover in the cab, undoing the heater hoses, and yanking the core out - elapsed time say 30 minutes. If mine was leaking I'd just cut it out of the coolant circuit by looping the hoses and live without heat but I don't suppose that's a viable option in Idaho.

Yeah, I'm scrawny also! It is so bad to get into the heater core that I would seriously look into some different type of heater. Maybe something could be shoehorned into the passengers foot space. Hmm, the one I parted took me forever to get the dash apart. Maybe I'll give it one more shot and actually follow the manual next time :juggle:

Mountainman · **Posted:** Sun Jul 05, 2015 5:57 pm

There were a few bubbles at cold idle, so I had the wife hold it at 2k, and they started streaming out 3x faster :banghead:

I know there was a lot of discussion of bubbles, but did anyone ever make a certain determination that this indeed a leaky head gasket? I would check one of my others, but only one is running, and it also has a bad head gasket with bubbles...

flash7210 · **Posted:** Sun Jul 05, 2015 6:45 pm

You can get a cooling system pressure tester at just about any auto parts store. Stant is a common brand. Dont know tbe prices. The CRD uses a standard size radiator cap, no adaptor needed.

Pressurize the cooling system to 16psi.
Pull the glow plugs and disconnect the injectors (or pull the ASD fuse).
Crank the motor.
If water comes out of the glow plug holes you will have your answer.

DOC4444 · **Posted:** Sun Jul 05, 2015 7:07 pm

Sounds like you waited too long to do the ARP only routine.........

Sorry, I had to do our HG, as well....

DOC

geordi · **Posted:** Sun Jul 05, 2015 7:45 pm

Is your EGR cooler still connected to the plumbing system? That is another high priority spot for water leaks that would be considered "silent" leaks and can show bubbles too.

4-5 feet of 5/8" heater hose to the port under the intake, routed across the top to the Y connection completely bypasses the EGR cooler and eliminates the hard pipe and about 8 different connections that any could be your leak point too... Although bubbles do suggest the gasket or the EGR cooler, sorry.

If you are game to try, head gaskets like this don't actually "go bad" unless they are rusting. You could pull the thing and spray both sides of it with CopperCoat or Hylomar - Permatex makes a product that I am not certain of the exact name, but it is a copper spray that looks quite pretty when done to the gasket and installed. This will seal any small leak points, but you would need to inspect the gasket for any possible exhaust gas traces - soot trails - that could indicate where the leak actually was. If there is **ANY** corrosion around that, the gasket should be tossed and replaced with new.

Doc's CRD still showed just the potential of a leak under heavy loading in summer, but don't forget that some "breathing" of water into and back out of the overflow section is also completely normal. The bubbles and the coolant alarm are the keys. Neither of those should be happening.

Mountainman · **Posted:** Sun Jul 05, 2015 8:15 pm

This one does still have the EGR (my daily driver I pulled it all), although when I had the FCV and elbow out yesterday I looked and felt all around, and found no water.

I read in another post where GMCTD asked if someone had bled the air out of the top of the radiator, which I didn't. I never do because that valve is always so tight that it feels like it will snap. Maybe this is where my air could be coming from.

Oh! I found where I forgot to slide a hose clamp back on on the side of the reservoir on the passenger side :pepper:

And, with the cracked radiator cap, maybe those two could have been pushing out 3/8" of fluid?

I'm still hoping it's not the gasket. I mean the bubbles deserve a better description. They are so tiny I had to use a light to see them, and they aren't streaming out fast, maybe one every few seconds, and then maybe two per second at 2000 rpm. hmm, let me check again with that hose clamp in place :5SHOTS:

If all else fails I'll be off to get the pressure tester kit. I don't think I'll try the one for one again, but then again, I hosed my back last one that I pulled the head on. Too much bending over

Srytrucker · **Posted:** Sun Jul 05, 2015 9:00 pm

pressure tester kit or the one from Napa for about 50 bucks or so it is a tube with chemical in it and changes colour when it detects exhaust gas in coolant. Mine had a leak in the tiny coolant return pipe near oil dipstick toward the rear of engine bay hard to reach place, It was an easy fix just got a 6 inch replacement pipe and it was done.

Mountainman · **Posted:** Sun Jul 05, 2015 9:40 pm

Thanks for all of the advice everyone! I'll keep at it. Like another guy said recently, at least I'm getting fast at taking it apart...

papaindigo · **Posted:** Mon Jul 06, 2015 9:16 am

Like every vehicle cooling system since ca. 1970 with what amounts to an overflow bottle the CRD cooling system is self bleeding for trapped air. As the coolant heats up it expands forcing excess coolant and trapped air into the overflow bottle. As coolant cools down that excess coolant is pulled back into the system without the trapped air. Enough cycles and any trapped air is purged. Is it best to minimize trapped air by opening that top radiator valve and filling the system until coolant comes out of the valve prior to closing it - of course but I suspect that if you do not all that will happen is you need a few more drive cycles to get rid of the air.

Mountainman · **Posted:** Mon Jul 06, 2015 11:57 am

papaindigo wrote:

Like every vehicle cooling system since ca. 1970 with what amounts to an overflow bottle the CRD cooling system is self bleeding for trapped air. As the coolant heats up it expands forcing excess coolant and trapped air into the overflow bottle. As coolant cools down that excess coolant is pulled back into the system without the trapped air. Enough cycles and any trapped air is purged. Is it best to minimize trapped air by opening that top radiator valve and filling the system until coolant comes out of the valve prior to closing it - of course but I suspect that if you do not all that will happen is you need a few more drive cycles to get rid of the air.

Thanks again :JEEPIN:

I think I'll go try to crack that valve open and see if that stops the few tiny bubbles that I'm getting. Prior to the ARPs it probably took 500 miles to consume 1 cup of fluid, so I'm still thinking that I'm ok, but time will tell I guess.

Geordi, I will do that EGR fluid bypass if I can't stop the bubbles since pulling the HG is crazy before I eliminate the other possible causes, and I already did a Yeti tune to shut off the EGR, so I'm guess it won't need water cooled anyhow :?:

Mountainman · **Posted:** Mon Jul 13, 2015 11:01 pm

I found another leak! You all think the hose that comes off of the bottom of the reservoir that goes to the water pump manifold could let in a few tiny bubbles? after adjusting the clamp on the reservoir end, and a few more warm ups, and pulling the bleeder on the radiator, I've got a lot less bubbles :rockon:

But, I still have a few.
Can anyone verify that with a good head gasket, that they have ZERO tiny bubbles if they shine a bright light in there and get their eye right up to the opening? I can barely see the few bubbles now.

That line I mentioned is definitely seeping on both ends. Come to think of it, the head gasket might have been good before I even started all of this, especially since I've found at least one leaky connection that I didn't touch during the ARP install, but I'm putting ARPs in all of them regardless...

ARPs not take, or a different leak?

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