: HeadGasket Repaired - cost $1500 - but more problems?...

10-04-09, 09:26 PM
Ok so the car was finally repaired... by a craigslist tech who did it for $650 & i paid for parts...

You may remember me from a few weeks ago... i had lots of questions... well it's riding now via norms... the temperature gauge has been slightly past the 1/2 mark but only a smidget. I also had RSS codes 0615 & 0620 which is probley a suspension sensor he left loose...

He said the job was a pain... but 500 miles later it appears to be fixed... until today...

a hose leading from the coolant area... hooking up to an very stiff rubber line that goes into the engine started spraying out coolant and emptied my whole reservior in a minute... the leak was where the nut screws on to the engine.

then the coolant temp ran to about 1 o clock... i'm scared as hell that could harm my fresh gaskets... i pulled over and waited till it was cool enough to drive 5 more minutes home...

i'm takin it back to him tomorrow... hopefully it was a minor mistake on his part... and hopefully running my coolant temp to the 1 o clock mark wont ruin the whole job!

10-04-09, 09:38 PM
Coolant temperature has no bearing on head gasket life. If the Northstar head gasket fails for any number of other reasons you have exhaust gas in the coolant which over pressurizes the system, blows off coolant, and then causes the engine to overheat. The hose to which you refer sounds like the heater inlet snap fitting at the firewall side of the water crossover area or the outlet connection at the pipe which goes to the area of the thermostat housing.

10-05-09, 12:39 PM
So heat does not effect head gaskets? temperatures of 250 degrees or so wont warp heads or pull bolts? i thik the 1 o clock mark is only like 235 degrees or somthing but i want to be sure... also...

is there a name for that hose that hooks to the back of the water crossover?

10-05-09, 12:56 PM
No, temperatures of 250 degrees will not warp heads or pull bolts. The bolts pull because the block threads fail from porosity in the casting or corrosion, then the gasket blows, not the other way around. Consider that the .040" head gasket compression line at the cylinder is sealed with a s/s ring in the gasket which is exposed to over 1,100 degrees of combustion temperature. At high rpm exhaust valve heads run on the edge of dull red, and that high heat is transferred directly to the valve seat, which is the only way the exhaust valve transfers heat to the head. Temperatures are all over the place in a running engine head/block interface. 250 degrees of metal temperature of the surrounding castings is COLD compared to combustion temps.

Well, yeah, but then why don't we run engines at 300 degrees for more efficiency? Because above 275 - 300 metallurgy (expansion and contraction) and lubricant abilities all go to hell in a handbasket.

I believe the name of the hose, in the FSM, is heater inlet hose. It has a special snap fitting arrangement.

10-05-09, 03:25 PM
I wish I could buy a few of you guys lunch... especially guys like submariner... and a few others... so knowledgeable about the highly mysterious n*... however very generous with your time...

Thanks a ton... thats good stuff there sub... I feel a billion times more at ease after going through the head gasket phase... Take this into consideration, shortly after my radiator cracked... i put 100% pure water instead of 50/50 dex for about 2 weeks and maybe only 150 - 200 miles worth of driving, during which time the temp gauge did not move much past, according to the helpful gauge u attached, about 220-225 degrees. I thought the HEAT is what cause the failure... I now know it was either the water... OR it could have been my often practicing of WOT's that has MY 2002 at the front of the line of many more post 2000's n*'s headgasket/headbolts bound to fail just like the past ones (the additional exhaust pressure in the coolant perhaps the CAUSE of the radiator crack?)...

anyways... the tech is headed to my place today to try and fix up that hose. The fitting that appears to be leaking (can be viewed from top, by putting you head near the coolant tank and look towards the upper-mid engine)... is a nut looking fitting... a long nut (no homo) about and inch and a half or 2 inches long that screws onto a solid threaded pipe that comes out of the right side of the engine but it points backward towards the cabin area... the hose the screw/nut fitting is attached to is a stiff rubber line about a maybe a little larger than a penny in circumference, but smaller than a nickles... the line resembles a question mark how it comes from out of the fitting curves around and leads to a larger rubber hose right next to the coolant tank... we would call that an inlet heater hose? any tips on gettin that thing leak proof? not an easy nut to get to...

I don't complain about stuff like this to my techs(especially after fixing a REAL problem), but while the tech is here... how would i have him fix the RSS codes he left me? 0615 & 0620 both the left and right sensors are unhooked i guess... or maybe it's just one sensor that connects to both that are unhooked... any ideas on where those are located?

Thanks so much again

10-05-09, 10:07 PM
You may be too worried about engine temps. I get this alot with customers. It is 100% normal for the temp guage to hit the 1 o'clock mark. I refer to this as the 5/8 mark for some reason. It should be right on 12 o'clock on the highway but get in traffic, and it's normal for the temp to creep up to 1 o'clock, that's roughly when the fans will kick in and knock it back down to mid-way on the guage.

As for the RSS codes, it is quite possible those codes were caused by him but remember your car is a 2002- anything can fail on a car at any given time. He will probably take care of this for you and it may be his fault, but Cadillacs are rolling electronics warehouses. I had C1235 flash on my '98 STS today. I've never seen it before, I cleared it; and it didn't come on again. I'll probably check the connection tomorrow.

10-05-09, 10:18 PM
That coolant connector should ALWAYS be replaced. That may be one thing he left out of the parts list. I retrofitted a few cars in the past with real threaded fittings instead; for some reason I just don't like quick connectors when it comes to oil pressure lines (some have that) and coolant lines.

I bet he probably re-used the original connector. Get him to change it. 1 1/8" socket or wrench in a hard-to-get-at place. These were used on:

95+ Aurora (All)
98+ Seville (FWD)
00+ Deville (FWD)
Bonneville GXP
Lucerne (N*)

The Eldorados don't have these connectors, neither do the 93-99 Seville, or 99 and prior Deville. Instead these cars have two steel coolant lines that run along the firewall and attatch with a short piece of hose and clamps.

10-06-09, 11:26 AM
I will admit I was too concerned about heat... only because the years previous to the gasket issue the temp gauge NEVER moved past 12 o clock. WOT, traffic, long drives... 12'o clock. But i now understand... it's OK to run slightly warmer than that, even coolant temp gauge at the 5/8 mark means nothin' as far as warping and damaging engine... Thanks much on the clarification...

As far as a coolant connector... i found what i believe to be the right hose on rock auto... coolant pipe D to heater core... However... I was not able to find the specific connector... what would it be called & what size? Is it something i can buy generically at a parts store

Also... any ideas on where that RSS module could be?

Thanks again!

10-06-09, 12:29 PM

I had long wondered chicken or egg, but based on my experiences and observations, I feel the most probable course of events is:

The HG corrodes over time and starts to leak, allows coolant and combustion gases to enter the head bolt hole in the aluminum block, and over time, the aluminum corrodes, weakens and finally releases the steel head bolt. With io clamping pressure, combustion gases are free to enter the cooling system, cause excessive pressures which blows out the coolant from the overflow, and then we get the overheating symptoms with which we are so familiar.

When I repaired my second N* with head gasket problems, I had:

1: Dry holes with good threads

2. Wet holes with good threads - I say "good", because the bolts were very hard to loosen and finally "snapped" when loosened. These bolts had a light coating of aluminum on their threads.

3 Wet holes with bad threads. These bolts did not snap - they were very easy to loosen - almost finger tight. these bolts, when removed, had a heavy coating of aluminum paste. They looked like they had anti-seize compound on them, but of course, it was the aluminum from the threads that had decomposed.

From what I have seen, it's the gasket that is the first to fail

10-06-09, 12:37 PM
I'll buy that, but it still isn't a result of high gasket/head temperatures, as the OP questioned.

For whatever reason, the head bolts/threads give up the ghost, but it's not from overheating: the overheating is a result of a compromised gasket.

10-06-09, 01:21 PM
I'll buy that, but it still isn't a result of high gasket/head temperatures, as the OP questioned.

For whatever reason, the head bolts/threads give up the ghost, but it's not from overheating: the overheating is a result of a compromised gasket.


I think if you overheat the crap out of an engine, you can cause the head gaskets to fail - or at least my brother did that one time when the thermostat stuck closed on a Chevy 6 cylinder engine in a '68 Bel Air - but we have limp mode that probably makes it impossible for us to do.

10-06-09, 02:19 PM
Thanks for the input thus far... i'm pretty clear on the temperature : head gasket relationship... however... I'm still learning about this heavily leaking inlet heater hose connector, does anyone have experience with this issue?

10-06-09, 04:34 PM
The quick-connect uses an O-ring or taper seal ring, and if it's cocked (not fully snapped in) or the ring is nicked, it will leak.

Good diagrams in the GM shop manual and Alldata.

You may find the quick connect (#1, first pic) on the "Help !" rack at a big parts house, but it is an unholy bitch to replace with the engine in the car. Check the threads - these engines are metric.

10-06-09, 05:00 PM
Bingo! that's the one... Thanks a ton sub... you guys make alot of cadillac service managers seems like autozone employees (no offense to autozone employees). In other words... you know you stuff up & down like you were at the drawing board up there at GM headquarters...

Ok so the metal screw nut doesnt need to come off... the hose should SNAP into place? I just finished messing with it... it does jiggle... showing some coolant dripping. I'll go back out and try and force it in further...

can i pull it out and replace the o-ring? Hmmm... Trying to figure out the fix...

Hopefully i wont need to take the nut off!

10-08-09, 01:38 PM
Ok i did it... for anyone else who has this issue... it wasn't NEARLY as hard as i thought it would be.... not quite easy but not hard at all...

I pulled the tube out of the connector after loosening the bracket that holds it up (13mm) then i used a 15/16 socket and a pretty small ratchet (to fit in there) to unscrew the connector.

I found a generic connector at the local advance auto parts, the "quik disconnect". It had a little plastic piece in there my old one did not have... the one that you squeeze to pop it out or snap it in. It seemed too easy and insecure to hold that type of pressure to me but... after installing and popping in the hose... no more leak... done... 20 minute job if you have what you need already.

thanks fellas for all your help!