Coolant leaking from back of engine somewhere?

**Mayron** · 09-02-2008, 09:56 PM

So I got a 00 T/A about two months ago

I imeadiatly changed the oil and coolant after a 500 mile drive home, well the next day

Anyways ever since then it's been eating a small amount maybe 12-24oz of coolant on a 50-100 mile drive. I kinda figured it was just working the air pockets out. There is no milky oil or radiator fluid so I didn't think it was a head gasket as it drove and idled fine. No smoke in the exhaust either. Well tonight I finally caught it leaking after a hard drive home. It seemed to be leaking down from two places, one spot just outside the drivers side collector (it's got spl long tubes) and one on the passangers side onto the tubes just before they merged into the collector. They were hot so it was evaporating when it hit on the p-side and I couldn't really tell where it was comming from. I took a light underhood and checked around and couldn't find any leaks but saw alittle liquid on the firewall below the heater core but it didn't seem to lead to it. If it helps the radiator seemed full when I checked just before I drained it originally after the long drive home. Any ideas where it could be coming from, from behind the engine on both sides? It's only 5-10 drops it seemed once I get in my garage so it's not a massive leak.

Thanks for any ideas or help you guys can provide.

Forgot to add that the ps fluid is red not orange cause I saw a post where someone thought the ps cooler was leaking some how. I know it's normaly clear but though it might be some fancy new HiPo fluid since im not the original owner, who knows whats in there. Looked under the car for the ps cooler and couldn't find it. I thought it was std for the ws6 but no leaks forward of the steering rack, its all coming from behind the engine ending up by the collectors on the ground some how.

**mike13** · 09-03-2008, 06:07 AM

Are you sure it's not the drain for the A/C?

**Spaz** · 09-03-2008, 06:11 AM

Originally Posted by Mayron

So I got a 00 T/A about two months ago

I imeadiatly changed the oil and coolant after a 500 mile drive home, well the next day

Anyways ever since then it's been eating a small amount maybe 12-24oz of coolant on a 50-100 mile drive. I kinda figured it was just working the air pockets out. There is no milky oil or radiator fluid so I didn't think it was a head gasket as it drove and idled fine. No smoke in the exhaust either. Well tonight I finally caught it leaking after a hard drive home. It seemed to be leaking down from two places, one spot just outside the drivers side collector (it's got spl long tubes) and one on the passangers side onto the tubes just before they merged into the collector. They were hot so it was evaporating when it hit on the p-side and I couldn't really tell where it was comming from. I took a light underhood and checked around and couldn't find any leaks but saw alittle liquid on the firewall below the heater core but it didn't seem to lead to it. If it helps the radiator seemed full when I checked just before I drained it originally after the long drive home. Any ideas where it could be coming from, from behind the engine on both sides? It's only 5-10 drops it seemed once I get in my garage so it's not a massive leak.

Thanks for any ideas or help you guys can provide.

Forgot to add that the ps fluid is red not orange cause I saw a post where someone thought the ps cooler was leaking some how. I know it's normaly clear but though it might be some fancy new HiPo fluid since im not the original owner, who knows whats in there. Looked under the car for the ps cooler and couldn't find it. I thought it was std for the ws6 but no leaks forward of the steering rack, its all coming from behind the engine ending up by the collectors on the ground some how.

are oyu sure it's not trans fluid??? could be running down the drive shaft and getting slung all over...

**Mean Green Z28** · 09-03-2008, 06:13 AM

What intake? LS6? Check the steam tube plugs at the back of the intake (you'll have to take the intake off to see), if those bolts get loose or the seal goes bad, they'll leak just like you're experiencing.

**Mayron** · 09-03-2008, 09:54 AM

Originally Posted by mike13

Are you sure it's not the drain for the A/C?

Yes, it's not water. The leaking fluid is orange and doesn't feel like oil to me between my fingers.

**Mayron** · 09-03-2008, 10:00 AM

Originally Posted by Spaz

are oyu sure it's not trans fluid??? could be running down the drive shaft and getting slung all over...

The drops of fluid are hitting the same spot on the ground so it's not like it's all over. It's more like it's dribbling somewhere and leaking down to a point before it free falls to the ground. Fluid seem like delcool on the ground as it's orange and not oil. The power steering fluid looks more like the trans fluid than the dexcool.

**Mayron** · 09-03-2008, 10:05 AM

Originally Posted by That Guy 2-1

What intake? LS6? Check the steam tube plugs at the back of the intake (you'll have to take the intake off to see), if those bolts get loose or the seal goes bad, they'll leak just like you're experiencing.

Ya know, I'm really not 100% sure. I guess it had the fast intake on it before but after it went through a couple people who couldn't afford it anymore; somehow it ended back up w/ a stock one painted that fast beige color. How can I id it? If I pull it off do I need new gaskets or can I reuse the current ones? I can't feel around the back side of the intake for those loose bolts w/o pulling it?

Thanks for the advice everyone!

**Mean Green Z28** · 09-03-2008, 11:10 AM

does the fluid taste sweet? if so, it's coolant. Don't drink it but a light taste wont kill you ... lol

You can reuse the gaskets on the intake. I guess you can feel around back, but it'll be easier to pull the intake to see exactly what you're doing ... only a couple 8mm headed bolts

**Mayron** · 09-04-2008, 02:12 PM

Originally Posted by That Guy 2-1

does the fluid taste sweet? if so, it's coolant. Don't drink it but a light taste wont kill you ... lol

You can reuse the gaskets on the intake. I guess you can feel around back, but it'll be easier to pull the intake to see exactly what you're doing ... only a couple 8mm headed bolts

I didn't get a chance to taste the fluid as it had all evaporated by the time I got around to the garage last night. It was too late to go on a joy ride and make it leak again too but I'd assume that if was any type of oil it would have left a residue on the floor.

I felt around the back of the intake manifold (man it's tight back there) and didn't feel anything loose back there. Where exactly would the coolant be comming from on the intake anyways, isn't it all plastic and there for, does not circulate coolant? I'll try pulling it in the next couple days to to make sure thought. Can I just disconnet the injectors @ the power or is it best to pull them out of the intake to keep everything connected? Anything other things that I can avoid pulling off or do I pretty much need to disconnect everything on, near and around it?

Thanks for the help!

**0rion** · 09-04-2008, 02:16 PM

check the weep hole in the bottom of the water pump and make sure it's not coming from there and if it's not then you can feel on the back of the heads at the steam ports and see if it's leaking back there. Look at the front of the heads and you'll see a little metal tube that goes to each head....the rear will be the same unless someone put an ls6 intake on there and went with the ls6 plugs in the rear in which case there will be plugs in those ports. I'd first check the weep hole and make sure it isn't leaking from there and running back along the oil pan or something.

**Mayron** · 09-04-2008, 02:39 PM

Originally Posted by 0rion

check the weep hole in the bottom of the water pump and make sure it's not coming from there and if it's not then you can feel on the back of the heads at the steam ports and see if it's leaking back there. Look at the front of the heads and you'll see a little metal tube that goes to each head....the rear will be the same unless someone put an ls6 intake on there and went with the ls6 plugs in the rear in which case there will be plugs in those ports. I'd first check the weep hole and make sure it isn't leaking from there and running back along the oil pan or something.

Thanks! That was exatcly the info I was looking for. I'll check it out tonight and see what I find. I have a feeling that's the issue. I'm guessing the FAST intake that was on there before I got the car would have been like the LS6 and had the plugs on the heads blocked off, right? I bet they came loose or something. Will pulling the intake give me better access to those plugs on the head or would I be waisting my time pulling it still?

Thanks again!

**0rion** · 09-04-2008, 04:51 PM

Originally Posted by Mayron

Thanks! That was exatcly the info I was looking for. I'll check it out tonight and see what I find. I have a feeling that's the issue. I'm guessing the FAST intake that was on there before I got the car would have been like the LS6 and had the plugs on the heads blocked off, right? I bet they came loose or something. Will pulling the intake give me better access to those plugs on the head or would I be waisting my time pulling it still?

Thanks again!

if you pull the intake you'll have direct access to those rear ports. I would rule out that pump first as it's pretty common for them to leak. When mine went it was pretty obvious though that it was up front. Look just below and behind the crank pulley.
I know I've read some pretty ghetto methods of dealing with those rear ports when swapping away from the LS1 intake so it's absolutely possible that something is up with those. I think it would be a fairly rare thing to have both leak at the same time unless they have a rear pipe between both that's leaking.

**Mayron** · 09-04-2008, 05:48 PM

Originally Posted by 0rion

if you pull the intake you'll have direct access to those rear ports. I would rule out that pump first as it's pretty common for them to leak. When mine went it was pretty obvious though that it was up front. Look just below and behind the crank pulley.
I know I've read some pretty ghetto methods of dealing with those rear ports when swapping away from the LS1 intake so it's absolutely possible that something is up with those. I think it would be a fairly rare thing to have both leak at the same time unless they have a rear pipe between both that's leaking.

I'm going to try and get it to leak in the garage right now to rule out it leaking from the pump. It looks clean up front but I'll know for sure w/ 0 air flow pushing the fluid around. Once I confirm it's not the pump and the car cools off I'll pull the intake and check for that leak behind the heads. I'm thinking there might be a crossover tube as the the front ports were redone w/ an line. I'll let you know what I find. Thanks!

**Mayron** · 09-04-2008, 06:18 PM

It's definately coming from the drivers side and it tastes sweet. I could actually see drops falling just below the last cylinder's exhaust port onto the header collector. I'm guessing it has to be from that port leaking right? I'll pull the intake off later once it cools off and check that plug. Don't suppose anyone has a picture showing the location or know about the the size of a bolt someone might use to block off the passage(we talking ~10 or ~15mm+)?

**0rion** · 09-04-2008, 07:13 PM

if memory serves me correctly it's a 10mm bolt on that plug. Look at the front of the heads and there's a coolant pipe going from one head to the other that passes under the throttle body. Those will be the same size as the plugs on the back. Those plugs have a little o-ring around them...that could be your problem.
Here's a pic I borrowed from ls1howto that shows the original 97-00 pipe. If you have an ls6 or aftermarket intake though they probably used the new way with a pipe across the front and plugs for the back. You can see the "block" on the drivers side head in this pic just above that rubber hose.

**Mayron** · 09-04-2008, 08:59 PM

So I'm stuck on the fuel line, manifold's loose but according to ls1howto I need a special tool to get the fuel line off?!? Is there another way and if not where would one get such a tool, Kragen/Autozone or is it a special order thing?

**Mayron** · 09-07-2008, 02:12 PM

Ok, I got the fuel line dissconected after picking up a decent set of spring loaded aluminium fuel line tools @ autozone. It's definatly coming from that back port. It never ceases to amaze me how someone can do all this work to an engine and then use jb weld

to block a cooling passage instead of just tapping it and installing a plug/bolt. I really wish I knew who did all this work so I could make it my mission to destroy their reputation and keep them from ever giving anyone any type of advice or work on a car again. Sorry just had to vent little. I'm just blown away by stupidity sometimes.

Anyways, I've already got a set of taps to thread that coolant hole but I thought someone else might have some experience on the process, like how far down to tap and what length/type of bolt or plug might work best. ls1howto reused the old line which I don't have so if anyone can provide any helpful info, it would be much appreciated.

**mike13** · 09-07-2008, 02:39 PM

Help me understand, there's a cooling passage in the head? intake? that isn't used so it needs to be plugged with a bolt or pipe plug? Is that correct?

**Mayron** · 09-07-2008, 03:42 PM

Originally Posted by mike13

Help me understand, there's a cooling passage in the head? intake? that isn't used so it needs to be plugged with a bolt or pipe plug? Is that correct?

Yep, pretty much. It's in the drivers side head where that red line in the pic above is running to up top. I think it's part of the cooling mods required for the ls6/fast intake manifolds, cause of the flat bottems right? I've actully been probing around w/ a piece of wire in the hole trying to gauge depth and I'm starting to lean more twords getting the proper fitting from gm and plugging it where the line would normaily go instead. Is that a reasonable thing to do or I'm I over thinking this?