: Mysterious loss of coolant / 7000 miles without a problem since new studs & gaskets..



tigers2007
06-23-11, 11:24 PM
I've put at least 7 to 8 thousand miles on this car since I had the engine worked on with new studs and gaskets. Its been running great with no problems until today. I was on my regular commute (about 40 miles of freeway) to work when I stopped halfway for a sandwich. I was in Jimmy Johns no more than five minutes and when I started the car up, I saw a cloud of steam come from under the hood and then as I pulled away there was a nice sized puddle of coolant. The engine temperature normally stays around 205-209. I immediately changed the display to the temp and it showed 251! Once I got back on the main road it dropped to the 220's. When I got back on the freeway, it dropped to the high 2-teens. I got to work, looked at it and there were no leaks. I could smell coolant but could find no leaks.

Before I left work tonight, I checked under and around the car and did not find any puddles. I got on the freeway and the temp rose to 225 and then dropped to 208. About ten minutes later it rose to the 240's and stayed there until about a mile from the freeway exit (Murphy's Law) when it shot up to the high 250's. I changed the HVAC temp to 90 and turned the fan to max. The temp dropped about ten degrees and I made it home safe with it peaking at 263.

I just took a look at it -- no leaks! I checked the oil -- no change in the level, nice and clean (changed it two days ago). I opened the radiator cap, heard a large rush of air and it looked very dry in there. I put about half a gallon of coolant (all I have) and it went in with no problem.

I inspected every joint and hose connection -- no leaks. Is there any reasonable explanation for this?

Submariner409
06-24-11, 09:30 AM
If you can find where the "cloud of steam from under the hood" is coming from, you have a starting place: it could be a leak, or worse, coolant blowing out the reservoir cap relief valve. (What pressure rating and condition is the cap ?) Remember to use the FULL COLD arrow on the reservoir as your cold fill target. Too much coolant and it automatically blows out of the relief.

While you're at it, do the flow test for the coolant system purge line. That can be a culprit in this, too.

tigers2007
06-24-11, 10:26 AM
Crap does anyone remember if Jake uses Dexcool or the regular green coolant? I just added some regular Peak green coolant (50/50 of course) and I can't remember if thats what Jake used when he does the jobs. I'm about to run up to the parts store for more coolant.

tigers2007
06-24-11, 10:46 AM
I just put suction on the purge line and its flowing free (sucked coolant out). I noticed that I have a orange/green mixture lol.

Ranger
06-24-11, 10:48 AM
If I remember correctly, Jake does not like Dex.

tigers2007
06-24-11, 11:03 PM
Update: Pinhole sized leak (1/8") discovered coming from a short coolant tube (1" diameter) on the drivers side. Looks like a heater core pipe that travels behind the engine. It is the lower tube. This looks like it will be a real PITA to replace. One of the clamps might have squeezed thru the green rubber tube.

maeng9981
06-24-11, 11:14 PM
I replaced the green tube with same kind (reinforced) of black tube. I had to splice mine while removing for stud work. It was squeezed to the point that it is no longer removable without damaging it. If I remember correctly, it will be hard to remove without removing all the surrounding coolant lines.

tigers2007
06-25-11, 12:39 AM
I believe it is part #19 in the diagram below that is the culprit - it is the lower of the two. Well I'm about 40 miles from work. I wonder if I can stretch this out. I have a gallon of coolant in the trunk. Maybe I'll run the heater the whole way to keep fluid moving instead of being under pressure?

http://www.compnine.com/largeimg/0104046M08-010.gif

89falcon
06-25-11, 01:22 AM
I believe it is part #19 in the diagram below that is the culprit - it is the lower of the two. Well I'm about 40 miles from work. I wonder if I can stretch this out. I have a gallon of coolant in the trunk. Maybe I'll run the heater the whole way to keep fluid moving instead of being under pressure?

http://www.compnine.com/largeimg/0104046M08-010.gif

If it's 19, it's not that tough to replace......the fact that "10" is also rubber allows you to move the pipe around some...

Am I the only one who thought the hose was non "original" the first time I saw it? A GREEN rubber hose? Really? So out of place....

Submariner409
06-25-11, 07:20 AM
Maybe I'll run the heater the whole way to keep fluid moving instead of being under pressure?

The heater circuit is a constant, full flow design. The "Heat ON or OFF" has absolutely no bearing on system pressure. (Heated air temperature is controlled by air blend doors, not heated coolant flow.)

Ranger
06-25-11, 12:57 PM
The hose IS OEM and is green because it is a silicone hose and is a silicone hose because it stands up to heat so much better and was used because it IS such a PITA to replace. DO NOT cheap out with a regular heater hose.

#5 & 6 are supposed to be a real joy to replace as well.

RippyPartsDept
06-25-11, 01:42 PM
:yeah:

JoeTahoe
06-25-11, 02:18 PM
if you are gonna do it I would change #8 and #10 also and dont go the cheap route, use only silicone hose as Ranger said. Jake does not use Dexcool.

tigers2007
06-25-11, 04:15 PM
It ended up being hose #8. What a real pain it was. I kept saying to myself, "I need to pull the engine. I need to pull the engine...". Finally after tugging and pushing with a pry tool, I got it jarred around enough to slip on a piece of hose after lubricating everything with coolant. I didn't get a silicone hose. As long as this can last a couple years, I'm happy with it. I once had a '96 Caprice that had all silicone hoses like that. I just can't believe how easy this one tore away. Was 12 years old though. I got the $1.20 Autozone heater hose 1ft section. Hell, I only need this to last me a few seasons. What a relief though --- I was starting to think it was the headgaskets!!!

RippyPartsDept
06-25-11, 07:56 PM
I doubt it will last one year. But at least you know what you're in for next time.

Ranger
06-25-11, 09:04 PM
I doubt it will last one year. But at least you know what you're in for next time.
Especially if it came from AutoZone.

MoistCabbage
06-26-11, 02:36 AM
'96 Caprice that had all silicone hoses like that.

It didn't leave the factory that way. As stated before, there's a reason your car uses the silicone ones there. I hope for your sake it holds up for a while. :)

stoveguyy
06-26-11, 11:07 AM
i changed mine with motor out. used oem hose. original ones shredded of course.

tigers2007
06-26-11, 11:35 PM
Yeah that wouldn't be a bad idea for Jake to offer new hoses like that. I would have paid extra to have them replaced. I think i'm going to wrap some foil around it tomorrow. Otherwise its been running great and a lot cooler --- regular temps before were in the 205-209 range. Today it was running in the 196-200 range.

97EldoCoupe
06-28-11, 07:25 AM
Actually MoistCabbage, The 9C1 Caprice's as well as possibly fleet vehicles DID have those "lifetime" hoses from the factory. My 9C1 did, it was a New York state police car and when I researched it, GM did that for police service vehicles.

Tigers2007 I apologize- I will make a note to replace those lengths of hose at all times from this point forward.

Green coolant only. I've seen way too many head gaskets that suggest dex is contributing to HG failure, possibly only if left in the cooling system extended periods of time. My '04 Bonneville GXP - head gaskets rusted right out. It was only 5 years old. That's proof enough for me. '93 Seville. Green coolant its whole life. Original HG's. HG's were perfectly fine, bolts were pulled.

97EldoCoupe
06-28-11, 07:47 AM
As a side note, if I see a cracked, damaged, or swelled hose, it always gets replaced. Rusty tubes, if it's only very slight surface rust and no pitting, I will brush the rust off and paint the lines to prevent further corrosion. I do get special requests all the time, to replace starters, a/c compressors, belts, idler pulleys, etc. It's all in what the customer wants to spend extra. If it's not listed as an option, doesn't mean that it isn't one.

I speak in regards to nobody on this forum- but I have had some customers who were too cheap to replace rusted heater pipes, oil cooler hoses, power steering lines, etc. No charge for added labor when it comes to these things, only parts costs. I have to be careful that I do not proceed without customer's consent when it comes to extra parts. Power steering pressure hoses that are visually soaked and leaking, and that $200 part (my cost at the dealer roughly) is too much extra to spend for some. When you're on a tight schedule and you can't get ahold of the customer (again Tigers2007 this is not directed at you) and you have to make a call "would he/she want me to replace this or not"..... If I do it, and it wasn't within customers' consent, it's coming out of my pocket. If it's only a $5 length of hose I wouldn't even bother adding that to the bill.

These forums have given me many great ideas. So Tigers2007, I believe I will take your great idea and offer a checklist of commonly replace parts and their cost, customer will have better ideas what certain items would cost- such as alternators, a/c compressors, starters, hoses, belts, tensioners, all parts external of the engine that are prone to failure due to age, mileage, heat cycles, etc.

Thank you :D :thumbsup:

tigers2007
06-28-11, 12:49 PM
Jake that would be great -- a list of add-on's to include common items that are difficult to replace. I never realized how much stuff is crammed in there. When I first look at this project I kept saying to myself, "I gotta pull the engine...I gotta pull the engine?...oh God...." I believe Gates and Dayco sell bulk silicone coolant hose. That could cut down costs. Regardless, I think it would be a great idea to "push" the idea to the customer that it wouldn't be a bad idea to replace some of those crazy-hard-to-get-to items. Point your customers to these threads as evidence of potential frustration!

Hell, maybe even off a full refurb package - replace all wear items (belts, pulleys, tensioners, timing chains, hoses, etc.) Wasn't Sheehan Chevrolet in Lansing, MI doing this with the Caprice police cars? It was my understanding that when they cancelled the Caprice in 1996, Sheehan was one of the few dealers in the country actually stripping a Caprice down to the frame and doing a full refurbishment and kept those cars running strong into the early 2000's.

tateos
06-28-11, 07:05 PM
I used regular black heater hose to replace all of the green silicone hoses, and they have all lasted for 3+ years in Phoenix heat with no problem whatsoever. I'm sure the silicone hoses are better and will last longer, but the rest of the hoses under the hood are regular hoses and are exposed to the same environment, so they should all last about the same length of time. And BTW, I didn't think it was that tough of a job.

Just my $.02

johnny kannapo
07-01-11, 06:39 PM
I am sure the conventional hose will last for a good long while.
It's just the difficulty in changing it and the fact that there is constant heat rising up off the exhaust directly.

This will cook it cause premature failure.

Mark C
07-08-11, 10:25 PM
I used conventional heater hose to replace that #8 hose section on my 97 STS when I did the head gaskets, lasted for almost 3 years and 45K miles when I sold it earlier this year. Never leaked a drop up till that time.

89falcon
07-09-11, 12:50 AM
I used conventional heater hose to replace that #8 hose section on my 97 STS when I did the head gaskets, lasted for almost 3 years and 45K miles when I sold it earlier this year. Never leaked a drop up till that time.

Yep, replaced both of my green ones with no problems to date.....

It's ironic that we consider the GM engineers to be so brilliant for putting the green ones there.....of course these are the same guys who couldn't figure out how to make the HGs last for over 10 years (yet a 20 year old did in his home garage....), and brilliantly tucked the AC compressor on the N*s in a spot hotter than the Chernobyl core.........The more I read about the N*s, the more I think the engine was the right engine for the wrong car.....they put it in DEVILLES!!!! How many N*s have EVER seen the north side of 4k rpms? The N* belonged in the STS (and the STS needed to be about 500lbs lighter...), and frankly the Corvette...and the SBC...LT1...belonged in the rest of the cadi line. Think about it...they put MAGNESIUM VALVE COVERS on an engine in a 4K lb car....how much weight did THAT save? Magnesium isn't exactly easy to pour.....