Losing coolant

Disturban · February 08, 2011, 12:06:40 AM

I am frustrated to say the least, the wifes truck is losing maybe 1 quart of coolant every 2 to 3 weeks. I cannot pin point where it is going...I put the black light dye in the radiator and see nothing. I sent in a oil sample to blackstone and they said no coolant in the oil and I get zero smoke out the tail pipe...Where is it going?

2000 Bravada, never had Dexcool in it's life, the original owner switched that crap out as soon as he bought it, we are the second owner.

I took it to the dealer and they pressure checked the system and it held 15psi for over an hour.

It is losing so little that it is impossible to track down where it is going. I suspect headgasket even though there is no coolant in the oil. Water pump went bad a few months ago and the wife ran it up to 3/4 the way on the temp gauge and I am thinking she fried a headgasket?

Oh well if I need to replace headgasket it is time to ad some power with a cam and marine intake! Guess I will deck the heads also just to make sure they are true...I dont think I have a cracked head but I might get them magnafluxed just to be sure before decking them.

Any other suggestions on where the coolant could be going or what to check? Or a way to for sure find the leak?

73chevytruck · February 08, 2011, 12:27:55 AM

possibly heater core?

Jr · February 08, 2011, 12:36:07 AM

Quote from: 73chevytruck on February 08, 2011, 12:27:55 AM
possibly heater core?

and heater cores are a byTch to do in them bravadas and blazers............. if oyu need any help or information on how to get it out pm me and ask me... ive cone prolly 10 of them... there not fun

Disturban · February 08, 2011, 12:38:03 AM

Quote from: 73chevytruck on February 08, 2011, 12:27:55 AM
possibly heater core?

Nope that is dry as a bone and I smell absolutely no coolant.

Disturban · February 08, 2011, 12:41:08 AM

Quote from: Disturban on February 08, 2011, 12:38:03 AM
Quote from: 73chevytruck on February 08, 2011, 12:27:55 AM
possibly heater core?
Nope that is dry as a bone and I smell absolutely no coolant.

Yep I already took it all apart to check it...fun fun job, took me about 6 hours, a lot of cussing and swearing, a lot of bear and a lot of tools thrown across the garage

I would have thrown a new heater core in it however the heat is fantastic so I know there is no blockage and everything looked like brand new.

Seen zero moisture when I got everything apart!

Jjay78 · February 08, 2011, 06:04:42 AM

does it pass through the overflow line to the ground after ya run it a while and shut it off? had a car do that to me before, took weeks to figure it out wouldn't run hot or anythign but everyonce in a while if i ran it for a while and shut it off it would fill hte over flow and then over flow that onto the dirt, just an idea man

doughchvy1 · February 08, 2011, 10:29:19 AM

check the trans. i had an internal trans cooler on a jimmy that went bad and was loosing coolant. pulled the trans cooler hose off and had collant come out of the hose.

Disturban · February 08, 2011, 01:31:11 PM

Quote from: doughchvy1 on February 08, 2011, 10:29:19 AM
check the trans. i had an internal trans cooler on a jimmy that went bad and was loosing coolant. pulled the trans cooler hose off and had collant come out of the hose.

Tranns fluid level is right on the full mark, I would imagine if it was leaking inside the radiator into the tranny cooler the fluid level would be past the full mark by now?

I guess that is possible though, I have dye in the coolant so I will pull the dipstick tonight when it gets dark and shine a black light on it, if any coolant is in the tranny fluid it will light up like a Christmas tree.

It is not overflowing the reservoir, brand new radiator cap.

Uncle Steve · February 08, 2011, 01:54:32 PM

intake gasket

see alot of it at work

MR NASTY · February 08, 2011, 02:08:24 PM

Have you pulled0all the plugs to see if there are any signs of coolant burning

Disturban · February 09, 2011, 12:45:13 AM

Quote from: MR NASTY on February 08, 2011, 02:08:24 PM
Have you pulled0all the plugs to see if there are any signs of coolant burning

Have not got that far yet but I see zero smoke coming from tail pipe.

MR NASTY · February 09, 2011, 12:58:46 AM

That's seems Like a small amount you probably won't

Squirell · February 09, 2011, 01:53:14 AM

My truck has the same problem, I found it to be a head gasket. Still haven't fixed it and I have put 5000 miles on it or more still no problems just add coolant every couple weeks

old school truck dude · February 09, 2011, 02:20:46 AM

Quote from: MR NASTY on February 08, 2011, 02:08:24 PM
Have you pulled0all the plugs to see if there are any signs of coolant burning

x2 also could the reservoir have a pin hole in it or otherwise be leakin somehow? Are you POSITIVE the RADIATOR coolant level is low, or are you just going by what you can see in the reservoir? Might be good idea to check coolant level in the radiator when its cold. Also maybe a pinhole in a hose spraying onto the ground or exhaust to where you wouldnt readily notice it??

If you pull heads for mill, be best to have them gone all the way through, saves a whole bunch of aggravation n fartin around later which for me has a funny way of endin up bein SOONER, lmao... I never put heads on anything without maggin first. Worked in the machine shops for years and youd be surprised, lots of them were "runnin good" but actually cracked!

Disturban · February 10, 2011, 08:59:55 PM

Quote from: old school truck dude on February 09, 2011, 02:20:46 AM
Quote from: MR NASTY on February 08, 2011, 02:08:24 PM
Have you pulled0all the plugs to see if there are any signs of coolant burning

x2 also could the reservoir have a pin hole in it or otherwise be leakin somehow? Are you POSITIVE the RADIATOR coolant level is low, or are you just going by what you can see in the reservoir? Might be good idea to check coolant level in the radiator when its cold. Also maybe a pinhole in a hose spraying onto the ground or exhaust to where you wouldnt readily notice it??

If you pull heads for mill, be best to have them gone all the way through, saves a whole bunch of aggravation n fartin around later which for me has a funny way of endin up bein SOONER, lmao... I never put heads on anything without maggin first. Worked in the machine shops for years and youd be surprised, lots of them were "runnin good" but actually cracked!

Yeah I fill reservoir to the full mark as well as top off radiator...2 weeks the reservoir is empty and the radiator is still full. If I go 3 weeks the reservoir is empty and I have to add some to the radiator as well.

I will mag the heads for sure thats a givin just for the fact that my coolant loss could be because of a cracked head...I got some money to play with so I am going to hop it up a bit with better cam, marine intake, 24lb injectors and a tune. Should get me close to the magical 1hp per CID.

With the marine intake it will have real fuel injectors that I can change to 30lb injectors in the future if I can get a deal on a Supercharger. I would love to have a 350-400hp Bravada nobody would ever suspect that

at a red light

MrCompton734 · February 10, 2011, 09:17:30 PM

Sounds nice. I plan getting around 400hp from my 318 once it hits 150k or so. Only at 88k now though.

Disturban · February 10, 2011, 10:18:17 PM

Quote from: mrcompton on February 10, 2011, 09:17:30 PM
Sounds nice. I plan getting around 400hp from my 318 once it hits 150k or so. Only at 88k now though.

This motor has 145k on it right now but has had a steady diet of Mobil 1 for the first 80k changed every 10k and we have used nothing but Amsoil SSO since we bought it changed every 20k. Used oil analysis shows very little wear and it goes through about 1 quart of oil in 20,000 miles so the bottom end is in pretty good shape.

The supercharger I am looking at for it is a wynjammer they only put out 6psi I think this motor would be just fine? With a cam, marine intake, upgrade fuel injectors and a tune and exhaust 250-260 hp is in reason, add 6psi bigger injectors and different tune should put me in the 320-340hp range, I did not just pull these numbers out of my ass I have been doing some serious homework over at S10 forums.

I would love to do a V8 swap and call it a day but the 1998-2001 Bravada's have a much more complex 4x4 system than previous Bravadas and it would be a nightmare to try and program a hybrid computer system to run both a V8 and the Smartrak...there is an option though of a 5.3 in a Chevy truck that has a computer to do this but it's just way to much work.

Disturban · February 14, 2011, 12:44:05 AM

Found the problem....intake manifold gasket for sure! Just needed to drive around more until it started leaking more, now it is going through a gallon every week and I can see where it is leaking...easy fix, better than a head gasket

ProGrade · February 14, 2011, 02:36:42 AM

Quote from: Disturban on February 14, 2011, 12:44:05 AM
Found the problem....intake manifold gasket for sure! Just needed to drive around more until it started leaking more, now it is going through a gallon every week and I can see where it is leaking...easy fix, better than a head gasket

yup intake gasket is only half the work! glad you found it! Those can be a bear because it pools up and burns off before it gets the chance to hit the ground usually.

Disturban · February 14, 2011, 05:30:06 AM

Well I guess it is not going to be a real easy fix because if I have to take the intake off I am doing everything right now, Marine intake, re-wire fuel injectors, cam, lifters, roller rockers. I would just be one step away from head gaskets...I might do them anyway and deck the heads a little to

compression, should keep me busy for a while. Taxes should be here any day then it is time to get parts...I think I will start taking it all apart tomorrow.