Heater Core Hose Intake Replacement

[sonar_91]

Folks, I have another problem, seems like I fix one, and another comes up to take it's place...I have a coolant leak.....they symptom is the coolant dripping down the back of the engine, I recently had to replace the gasket for the oil filter bypass, so it looks as if I am going to have to pull the upper intake manifold off, I had to do this once before, (for a failed gasket...causing a misfire on #8)but I had a ASE certified mechanic helping me all along the way and it was several years ago... I know I am going to have to disconnect the battery (-) side, disconnect the fuel lines, pull the coil packs, pull the plugs, disconnect the main wiring harness, possibly pull the fuel rails, and then pull the upper intake manifold just to access the hose. The leak is getting progressively worse- all to replace the a $17 hose(add an additional $88 for the intake manifold gasket kit)....which BTW cannot be ordered from the dealer....is there a chapter in the Haynes repair manual for this?, and if so, where can I find it? any help/pointers is greatly apprecieated

[miamibob]

I would either look for a video/s on YOUTUBE and/or get an OEM Service Manual (EBAY, maybe??). I consider the other manuals next to useless!!

[IPreferDIY]

Are you talking about the 02 MGM listed in your signature? If so, do you mean the heater tube that runs from the back of the water pump underneath the intake manifold to the heater hose? Those tubes can develop corrosion holes. Also, do you still have the original intake manifold with the plastic coolant crossover on the front? If so (and perhaps even if not), the part of the intake manifold where the other heater hose goes could also be the source of a leak. If you still have the original intake manifold, you should replace the whole thing with one that has an aluminum coolant crossover no matter what. The standard replacement would have gaskets already incorporated into it, so I'm guessing yours hasn't been replaced yet if you only changed the gasket.

... I consider the other manuals next to useless!!

"next to useless" might be a little extreme, but close enough. What really gets me is that the people who make those manuals seem to have no idea about what you really need to know. You always have to supplement with another source.

[sonar_91]

yes, I am referring to the 02 GM in my profile....I had to search hard and long to find out how to change the oil filter bypass gasket...and somewhere in that search I ran across the symptoms of my coolant leak meant that the intake hose for the heater core is leaking by..... that hose is about 6" long and preformed with a 90 elbow..and the ends are different sizes...as for having the plastic cross over or aluminum cross-over...I have no idea...yet........ but judging from you post...I have the plastic one...the leak runs down the back of the engine and only when running...there are no leaks up front...I have checked all accessible hoses very carefully and the water pump as well

[IPreferDIY]

I'd be guessing it's something that the hose is connected to rather than the hose itself, but anything's possible. Here's a link for a thread dealing with an intake manifold replacement:

http://www.grandmarq.net/vb/showthread.php?51319-2000-Grand-Marquis-Miss-fire-but-no-CEL&p=742628&viewfull=1#post742628

It includes other links that should be helpful. Updates and requests for further information are always welcome.

P.S. I tend to watch videos at high speed to get through them quicker. The ones on YouTube usually have a speed setting under the gear symbol.

[IPreferDIY]

I was just looking through that thread and realized that your 02 would probably already have an upgraded intake manifold that would probably not have the gaskets incorporated into it. (AFAIK, they changed the intake manifolds in 01. I was thinking 03.) The aluminum part across the front is the key thing.

[sonar_91]

yeah..mines aluminum, fun times this week-end....my '55 Packard is sooooo much simpler....

[sonar_91]

I went at it today full bore...and I realized something...yes I have the upgraded manifold....but when I had a mis-fire in #8 about 4 years ago and oil in the hole....I replaced the upper intake manifold gaskets...not knowing that this manifold doesn't require them....(there were gaskets present when I pulled the manifold off, and naturally replaced them) but I have coolant in the hole now...and have to replace the boots.....so...another two weeks to buy more parts....my question is this...should I inspect the the O-ring gaskets on the intake manifold and just remount the intake manifold....or err on the side of caution and just order a replacement manifold and start fresh?

[IPreferDIY]

Just to be on the safe side, I'll point out that I've only worked on my 2000, so I don't have first-hand experience with a 2001.

I found the following link that indicates some 01's had all plastic intake manifolds:

http://www.crownvic.net/ubbthreads/ubbthreads.php?ubb=showflat&Number=2287741&page=all

There's a photo about halfway down that thread showing the gasket strips for manifolds that do not have the gaskets incorporated.

It sounds like you had such gasket strips when you took off the old manifold, and then included new gasket strips even though the replacement manifold already had its own incorporated gaskets. Is this right?

Also, when you say oil in the hole, do you mean the spark plug holes? And could it be coolant rather than oil? I had coolant accumulate in one or two of my spark plug holes, but it wasn't obvious to me that it was actually coolant until I discovered the source of the leak.

It's basically a judgement call as to whether to replace the gaskets or not. Replacing them would be the safest bet. You should be able to get a kit with just the gaskets so you don't have to replace the whole manifold. If you go that route, make sure you inspect the manifold carefully first to ensure that no cracks or other defects have developed. Even the ones with the aluminum crossovers can develop problems because they still have a layer of plastic under them. Also, the part that the heater hose connects to might be plastic and can develop cracks.

[SVT98t]

Sounds like you have the Dorman manifold.
I just bought an intake manifold gasket kit from rockauto for $26.
No need to order from the dealer for common maintenance parts.
Plus, use the discount; RockAuto sponsors GMN.

-ryan s.

[sonar_91]

Ok , been doing more research...the manifold is the upgraded OEM manifold, not the Dorman manifold, so gaskets are required. The leak appears to be coming from the thermostat housing where the bottom of the manifold and the housing meet, if this isn't repairable, O'Riely's has a Dorman in stock that I can get for about $175. and yes when I said coolant in the hole, I was referring to the spark plug hole, so now I have spark plug boots to replace as well- now if I can just get that bracket in the back off....it has no purpose but to hold a retainer clip for the throttle body cables..it's going to make a great fishing weight. I didn't replace the manifold- just the gasket strips- I had no Idea 4 years ago about the different manifolds- but it appears that I did everything correctly.

[sly]

there should be an O-ring on the thermostat that can be replaced. It's different than the one that comes with the tstat. the two bolts that hold the housing on come right out, but you HAVE to put them back with no more than 15 ft-lbs of torque or you risk breaking stuff. the o-ring should be on top of the tstat.

[IPreferDIY]

Ok , been doing more research...the manifold is the upgraded OEM manifold, not the Dorman manifold, so gaskets are required. The leak appears to be coming from the thermostat housing where the bottom of the manifold and the housing meet, if this isn't repairable, O'Riely's has a Dorman in stock that I can get for about $175. and yes when I said coolant in the hole, I was referring to the spark plug hole, so now I have spark plug boots to replace as well- now if I can just get that bracket in the back off....it has no purpose but to hold a retainer clip for the throttle body cables..it's going to make a great fishing weight. I didn't replace the manifold- just the gasket strips- I had no Idea 4 years ago about the different manifolds- but it appears that I did everything correctly.

It sounds like you're talking about the plastic part of the manifold under the aluminum. There should be a gasket between the plastic and the aluminum. There might be bolts securing the plastic to the aluminum, but I doubt they sell that gasket as a separate unit (though maybe one of the gaskets in the Dorman gasket kit might be the right size). Another possibility is that the plastic under the aluminum might be cracked, in which case you'd probably have to replace the entire manifold.

You should be able to get away with just cleaning the spark plug boots. They come off the coil, so you can clean them separately, and make sure the metal conductor spring-looking thing is clean too. You can also buy the boots separately if you don't want to reuse them. Put dielectric grease around the lip of the boots where they contact the spark plugs to provide a bit of a barrier and to prevent the boots from sticking to the spark plugs.

If you mean the bracket that covers the corner of the fuel rail on the driver's side at the back, it's actually a crash bracket to prevent damage to the fuel rail in a serious crash. I've seen at least one person claim they could get it off without taking off the windshield wiper motor housing, but I didn't see an easy way of doing that so I took the housing off. Big PITA. Some people cut the bracket in half so they don't have to bother with the rear nut/stud, but that defeats the safety purpose.

[sly]

those bolts that hold the plastic to the aluminum part are just for positioning. they don't provide the sealing pressure. the bolts on the t-stat housing do that. may just need a snug in that case.

[sonar_91]

so here is the the area I think the leak is coming from sorry cannot add a call out...but it is where the tstat housing meets the plastic part that mates with the block...