shhwing

I discovered that I was losing coolant, but the obvious places were bone dry. I finally discovered that the leak was seeping out of the drivers side, second oil pan bolt back from the front of the engine, oil pan gasket. My first fear was water in the oil. There was none. A couple of calls to the dealerships here in Phoenix revealed that although this is not a common problem, they have seen it before. Apparantly I have to replace the intake manifold gaskets. Somehow coolant is getting past the manifold gasket, down a passage that exits on the, or near the oil pan gasket. My question is what kind of special precautions do I need to look for when R&Ring the gaskets? It looks as though I can disconnect the fuel intectors at the fuel rail and leave them in the manifold. Is there anything that I need to watch out for in changing these gaskets?

wolfman jack

have you ever had the intake off of your car? it has been some time since i have had an intake off of one of these cars but i thought that the only place in the intake that there is coolant should be at the t/b.

Hugger

iTrader: (21)

I also have this problem, It never seems to lose enough that I am missing coolant, I check it often. I looked all over and the only place that I could figure that I comes from is the water pump. My intake has never been off the car. I would be interested to hear people's opinions on this problem. I would like to know where it's coming from before I start trying to fix it.
-Josh

LS171Malibu

shhwing,

After a close look at a bare block and a long block I have in the garage, I feel thet there is no way you could have a source for water from the intake manifold gasket. Two strong posabilities(sp?) of a source would be the freeze plug on the drivers side, above that bolt...or the coolant temp sensor above that, in the head. Check for a path from one of those locations and then the left water pump gasket. Let us know what you conclude, good luck.

shhwing

The intake was removed to replace the top knock sensor, under warrenty, at 28,000 miles. I looked at the invioce and it states a gasket set was used. My block is spotless so it was east to see this leak. It seeps out slowely from the oil pan gasket. Nothing above or below is wet. I wipe the coolant away and wait a few seconds and can see it coming out again.

LS1swap

I am sorry but your dealer is full of B.S. An ls1 intake is dry ( i.e. no coolant going through) if you did have coolant in the intake you would have big problems. If it is not in the oil it is not coming from the pan. It is remotely possible that you have a porosity problem in the block and the water is leaking from the water jacket through that bolt. As mentioned above the most likely choices are water temp sensor, head gasket ( it is possible to leak outside the block and not in), or the freeze plug.

LS1swap

If I were you I would take that bolt out and start it up and bring it up to temperature. If it is porosity it will probably leak pretty steadily.

shhwing

I had thought of the porosity possibility, the weird thing is that it is seeping at the oil gasket. I just jacked it up and ran it. Nothing from the freeze plug nor the temp sensor. I wish that I had a diagram of the coolant passeges or a print of the block in general to trace where the coolant is coming from. As far as the dealerships advice, I phoned two different ones and they both reported that replacing the intake manifold gaskets will solve this problem.

Richie Carbone

iTrader: (3)

If your dealer replaced a knock sensor they had to remove the coolant transfer pipe(the shiny thin pipe that runs under the intake) it has 4 gaskets(one at each corner)and if the dealer lost one while replacing the pipe then that could be the source of your leak.

LS1 swap is correct, the intake is dry.

Some of these dealer techs make me want to <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" />

LS1swap

I honestly don't know the layout of the water jacket either, the bolts to the pan do head up the skirts of the block. Just how close they come to the water jacket I am not sure. as far as the intake gasket. I still don't see the possibility. Just for the sake of augment if it did leak there the coolant would run off the front or back of the engine for the intake is in the valley. But like I say it can't because coolant never runs through it. Did they possibly say head gasket??? I wish I could post a pic for you. If you saw the bottom of an intake and the mating surface of the head you would see there are no coolant passages. On older SBC it does, but not on an ls1.

LS171Malibu

If you know there is not a path of water from above, in front of, or from the aft of that bolt, I hope it is in waranty... any water originating from the described location is going to be a block problem. In fact, if it is not under warranty I would leave it alone unless it was leaking really bad.

Slowhawk

iTrader: (12)

I have a leak near the place you describe <img border="0" title="" alt="[Frown]" src="gr_sad.gif" /> Haven't looked at it yet,but I'm figuring it's a Head gasket(cometic) problem.I'll look into it soon since I'm installing another set of Heads.

shhwing

Does anyone have a GM factory service manual that they can copy and fax to me the R&R proceedures for the intake manifold gaskets?

Dave Carney

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Richie Carbone:
<strong> If your dealer replaced a knock sensor they had to remove the coolant transfer pipe(the shiny thin pipe that runs under the intake) it has 4 gaskets(one at each corner)and if the dealer lost one while replacing the pipe then that could be the source of your leak.

LS1 swap is correct, the intake is dry.

Some of these dealer techs make me want to <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Ditto. <img border="0" alt="[chug]" title="" src="graemlins/gr_chug.gif" />

LS1swap

Here is a good link. it details how to install an LS6 intake
http://www.ls1howto.com/index.php?article=5
your intake gaskets will be PN: 12533587 (you need 8)
and the vapor vent line seals are PN:12551933 (you will need 4)
replacing the vent line seals may be a good idea for they might have had them apart when they replaced the knock sensors. but once you have it apart you will see the intake gaskets have nothing to do with it.

LS1swap

Please take a look at the 9th and 10th pictures in the link I gave you. The one shows the bottom of the intake and the other shows where the intake mates with the heads. If you enlarge them you will see there are no coolant passages in them. So there is no where for coolant to leak. The small pipe that the knock sensor harness is attached to is the vapor vent line ( it is designed to prevent air pockets from forming in the heads.) I know I am just some guy giving advice over the Internet which has to be taken with a grain of salt. But I am trying to save you allot of work. Your dealer is giving you bad advice. They shouldn't have even taken the vent line apart because they didn't have to to replace the knock sensors. But who knows about GM techs.

66LS1NOVA

LOOK! THERE ARE SOME GM TECHS OUT THERE WHO ARE COMPLETELY FULL OF **** SIMPLY BECAUSE THER ARE IGNORANT CONCERNING THESE ENGINES AND THINK THE CUSTOMERS ARE TOO BUT, "THAT DOSENT APPLY TO ALL OF US!!!" NOW YOU GUYS ARE ABSOLUTELY CORRECT, THE INTAKE IS DRY, AND THE DEALER THAT TOLD YOU THAT IS PROBABLY FULL OF ****, I HAVENT HEARD OF OR SEEN THIS PROBLEM AND MOST OF WHAT I WORK ON IS THE GEN3 ENGINES, THE MOST COMMON I HAVE SEEN IS THE WATER PUMP GASKETS LEAKING DOWN THAT FAR, BUT YOU ARE ABLE TO SEE THE TRAIL GOING TO THE OIL PAN BOLT. WHAT YOU ARE DESCRIBING DOSENT AGREE WITH THE WATER PUMP THEORY. NOW, I WILL CHECK TOMORROW AND FIND OUT IF ANY DEALERSHIP IN THE US HAS EVER RUN ACCROSS ANY KIND OF A POROSITY PROBLEM WITH THESE BLOCKS THROUGH OUR DEALERSHIIPS NETWORK AND LET YOU KNOW, STAY TUNED FOR THE RESULTS AND I WILL POST THEM HERE, IN THE MEAN TIME, STOP WITH THE GM TECH BASHING BECAUSE IT DOSENT APPLY TO ALL HAVE A NICE DAY <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

shhwing

Thanks for the link to the R&R instructions. One thing that I am confused about. You state that the shiney tube is a vapor vent line, but the intructions clearly refer to it as a coolant transfer line and it does feed the TB with coolant. I understand that the intake gaskets have nothing to do with this leak, but let's say that the front, left coolant line gasket...o-ring... what ever it is, has been damaged and coolant was coming out there. This would of explained how water soaked my knock sensor and damaged it, but doesnt explain how it water is coming out where it is. Any thoughts?

shhwing

Disreguard my last post, I feel like a friggin idiot. I went out and looked under the hood and realized that the coolant transfer lines are external to the intake, bolted directly to the heads. They are bone dry. Now I have not a clue as to where this leak is coming from.

LS171Malibu

Take that bolt out and run it... let use know what it does. If it leaks more, at least you can rule out any other source. Next I would wait for the engine to cool to room temp, then clean the bolt and the inside of the hole the best you can with a good greaseless solvent. After that put a good bit of thread sealant on the threads and re-install the bolt making sure you don't strip the threads, and give it time to cure(over night or more). See if that helps.