Water pump gasket issues LT1
#1
Teching In
Thread Starter
Join Date: Jun 2019
Location: Rothwell, Northants, UK
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Water pump gasket issues LT1
Hi All. I'm new on here BTW. So I have a '96 Z28 LT1 in the UK. Her biggest issue is she only recorded 260 miles in the ten years before I got her, had her for 3 years. Almost all rubber parts have now been replaced, she's done 50k miles. So last year she started a dribble from the pas side of the water pump, nothing excessive. Took her to pieces, WP bolts were loose, replaced WP anyway and did all the oil seals at the front while I was down there, opti off, good clean and back together again. I was left with a small coolant problem loss problem which was the rad cap. You can pressure test these easily from the bleed screws? New rad cap, problem solved. She runs like a dream. Almost exactly 12moths later (only 4k miles), huge coolant loss all of a sudden. Not had her apart yet but looks like coolant leak in same place, right pass side WP gasket. Had a look today, Right hand bolts loose , left OK, gasket pieces visible. When I did the front I used a felpro gasket kit, used the pump gaskets in the kit not the ones with the WP. They seemed very thin? Just measured the ones that came with the pump (which I kept .. phew!) and they are 30 thou thick. Bolts were correctly torqued when I did it, but now loose? Pressure test reveals a constant stream of coolant so I guess I need to take her apart again. I read the posts on this forum ... Is this a thing with the LT1? What do you good people think?
Tom
Tom
#2
I have always used the FelPro WP gaskets but I also use a skim coat of RTV on each side of the gaskets. I use Permatex WP/Thermostat housing RTV, grey in color.
The drivers side, lower, WP bolt goes into a water jacket so thread sealer must be used on that bolt. Many just put it on all the bolts which may also help them stay tight although that should not be necessary
The drivers side, lower, WP bolt goes into a water jacket so thread sealer must be used on that bolt. Many just put it on all the bolts which may also help them stay tight although that should not be necessary
#4
TECH Regular
Always used the FelPro gaskets and never had a leak. Don't even coat with RTV. Just seal the bolt threads, torque, and go. Make sure the mating surfaces are super clean and free of any old gasket or thread sealant, and make sure your water pump surfaces are square and true. Some of the cheapo chinesium parts can be wildly out of spec.
#5
Yeah Dan, the gasket itself "should" be sufficient to seal and does on "new" fresh engine/WP surface but I find some mild pitting on my now 20 year old original AC Delco core (EWP) which has now been on my stock, H/C and 383 motors so it has been on/off several times during its life. Engine block has had old gasket scrape and wear/tear also. It is for these "imperfections"
that I use a skim coat of RTV on WP gasket. Also the skim coat holds the gasket in place during install. As you note "offshore" clones are marginal in every aspect, including casting/finish compared to original equipment
I hate doing the same job twice because a gasket leaks so I use RTV. Same thing on the one piece pan gasket, which is re-usable, that says no RTV required......I use it on the curved F&R and run it up 1" on the Flat. Like WP swap....I certainly don't want to do pan again if the gasket is leaking
OP, IDK why your WP bolts are backing out....they from my experience don't. Can't recall what TQ spec is but I have just always gotten them "tight" by hand ratchet and not had a problem
Thread sealer on at least the lower DS WP bolt. Thread sealer and RTV are 2 different things
that I use a skim coat of RTV on WP gasket. Also the skim coat holds the gasket in place during install. As you note "offshore" clones are marginal in every aspect, including casting/finish compared to original equipment
I hate doing the same job twice because a gasket leaks so I use RTV. Same thing on the one piece pan gasket, which is re-usable, that says no RTV required......I use it on the curved F&R and run it up 1" on the Flat. Like WP swap....I certainly don't want to do pan again if the gasket is leaking
OP, IDK why your WP bolts are backing out....they from my experience don't. Can't recall what TQ spec is but I have just always gotten them "tight" by hand ratchet and not had a problem
Thread sealer on at least the lower DS WP bolt. Thread sealer and RTV are 2 different things
#6
Teching In
Thread Starter
Join Date: Jun 2019
Location: Rothwell, Northants, UK
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Hi all and big thanks for all the responses. I've done many WPs on other cars and never had a gasket go so quick, in fact never done a WP twice. Useful to know that lower DS bolt is in a water way. Will pay special attention to that this time. I suspect that the previous slow leak was there for many years and may have taken some of the block away, pitting etc, perhaps not so obvious with old eyes! Agree with the chinesium comment and tolerances. I still have the pump I took off last year and actually faces look really good, but have no idea if original, so it's the block I suspect. When I fixed the old pump I found the PS bolts literally finger tight hence leak. Gona check the bolt lengths before I do it again and make sure the top two are not bottoming in case the WP casting is thinner. I say this because when I re torqued on Sat morning, they just went loose to tight, no tightening .. we'll see! DS is studs from memory, with coil and smog pump mounts. Can get the grey type RTV locally so will use that this time. At least I know how to do it. Had the rad and fans out last time to give more room but think this time can get at it without that hassle?
I'll let you know what I find, hopefully get a break from the day job on Friday and sort her out. Many thanks to all of spending time to respond, quite a source of information and experience! Here in the UK, no one even knows what she is!
Best Regards
Tom
I'll let you know what I find, hopefully get a break from the day job on Friday and sort her out. Many thanks to all of spending time to respond, quite a source of information and experience! Here in the UK, no one even knows what she is!
Best Regards
Tom
#7
TECH Regular
Trending Topics
#8
https://www.permatex.com/products/ga...licone-gasket/
Gotta be cool to have a LT1 car over there :-)
#9
Village Troll
iTrader: (2)
It doesn't matter whether you use sealant or thread sealer. Both will do the job. Only the two bottom bolts on each side of the w/p need sealer/sealant. Those are the only two that tap into water jackets.
#10
Teching In
Thread Starter
Join Date: Jun 2019
Location: Rothwell, Northants, UK
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
This is the RTV I use. Not sure if there are other types of "grey" RTV but this is designed more for coolant/water sealing
https://www.permatex.com/products/ga...licone-gasket/
Gotta be cool to have a LT1 car over there :-)
https://www.permatex.com/products/ga...licone-gasket/
Gotta be cool to have a LT1 car over there :-)
Tom
#11
Teching In
Thread Starter
Join Date: Jun 2019
Location: Rothwell, Northants, UK
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Hi. I don't understand ... sorry :-)
Might be being thick :-) I can get headlights here, the square sealed flat beams are symmetrical so are good for driving in the UK on the other side of the road, with just a tweak with a screw driver.
T
Might be being thick :-) I can get headlights here, the square sealed flat beams are symmetrical so are good for driving in the UK on the other side of the road, with just a tweak with a screw driver.
T
#12
Teching In
Thread Starter
Join Date: Jun 2019
Location: Rothwell, Northants, UK
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
So, the plan was Friday so the heavens opened and it stopped this morning! Been on it about 3 hours on and off between beers. Most of the time is getting the smog pump and bracket off, very much an after thought by GM. WP is out and just spent a lot of time cleaning the faces. PS side lower bolt started poring coolant as soon as I undid it and not much gasket left on that side so that's the answer. DS was stuck fast. Good news, I was worried because there's a core plug just out of sight on the PS but its clean and dry. Didn't drop fans, just took out the 4 bolts holding the PS side fan and lowered it and the WP came foo fine. So halfway more or less. All the oil seals I did last year are nice and dry.
My best friend, Oscar, can't join me because he might lick the coolant. The new stuff has some chemical that gives it a bitter taste to stop that .. good idea!
Tom
My best friend, Oscar, can't join me because he might lick the coolant. The new stuff has some chemical that gives it a bitter taste to stop that .. good idea!
Tom
#13
TECH Regular
Noticed you had a Z. The b-body euro lamps are called "T84's" here in the us, and they have a much better throw pattern than the b-body DOT's. T84's sell for over a grand on this side of the lake.
#14
Teching In
Thread Starter
Join Date: Jun 2019
Location: Rothwell, Northants, UK
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
She's Canadian built for export to Japan then imported here in 2006. When I'm allowed I'll post a pic of the door codes. She has 30 ani leather seats but is not a 30th model.
Future issues ... dash pad has a big crack, tinternet says it'll be in lots of pieces if I take it out. Tyres (or tires). I got two rear no issue 2 years ago (originals were old and cracked). I couldn't get two for the front, ended up importing them for the supplier up the road, £75 each (not bad!). You can't buy 245/50ZR16 in the UK, they don't exist. It has a space saver which is OK but, I'm not gona be seen driving her with that on! So I have to save up for new wheels, 17's and you can get 245/45ZR17 any where and the speedo will still be good.
Rear lights ... Europe allows red blinkers, UK, it's off the road, not allowed. Some get away with it ... it's a grey law. Blinkers have to be amber. Mine has amber blinkers but there is a small growing crack, currently across the reversing light .. which you don't have to have here. Once it hits the blinker .. issues. But, there is man who has fitted orange LEDs into red lens blinkers and from the led, the wavelength is so narrow, it shines orange! And red rear clusters from the US are relatively cheap :-)
Oh, and the cheapest gas here is £5.80 a imp gal, that's about £4.80 per US gal .. $6! 100 octane (RON) is $6.80 but I get a lot less issues if I run her on good gas like stuck EVAP solenoids etc probably because of all the cleaning additives. I get about 27mpg on a long run, 15 ish locally, WOT, you can actually see the gauge go down.
It's so much fun owning such a beautiful example of US muscle in a country where a government, what ever their political slant, really don't seem to like me having so much fun! What a machine! I'll never sell her.
Tom
#15
Teching In
Thread Starter
Join Date: Jun 2019
Location: Rothwell, Northants, UK
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Still raining! It's supposed to be summer! Starts getting darker next week! Got the last few bits on this morning, coil pack, reconnected DS ignition leads which you have to pull out to get at the bolt for the air pump mount and hoses all done Filled her, bled her, filled her again, bled her again enough so I can turn her round so she's on an up slope. Filled her again and bled her again. Took her out and all's well! Back on the road. What a machine :-). Still scaring the various Eu offerings that cost 10 times as much.
Next job, I ought to show my old GM Omega some TLC, maybe an oil change and a filter or two, clean out the breathers, 17 years old, cost me £200 to buy, since spent £65 on parts in 2 1/2 years. My daily runner, she never even let me down when the left hand coil pack split in half. A gorgeous little 2.6 V6 and four cam shafts.
Thanks for all your help and encouragement.
Tom
Next job, I ought to show my old GM Omega some TLC, maybe an oil change and a filter or two, clean out the breathers, 17 years old, cost me £200 to buy, since spent £65 on parts in 2 1/2 years. My daily runner, she never even let me down when the left hand coil pack split in half. A gorgeous little 2.6 V6 and four cam shafts.
Thanks for all your help and encouragement.
Tom
Last edited by black5f; 06-15-2019 at 10:53 AM. Reason: typo
#18
I do have a question for you. If you ever had your side wing mirrors broken, is there a place in England that reproduces LT1 f-body wing mirrors? The reason I ask, I would like to get a pair for my car in the United States. The first benefit would be having a convex driver side door mirror versus the flat mirror which requires me to buy auxiliary blind spot mirrors, second I fancy the styling of the these breakaway European mirrors, and third they are breakaway mirrors compared to the solid ones I have and breakaway mirrors are now a common standard option on cars today.
#19
yep, absolutely post pics/videos of your ride
….and the comment on the light engine blip (rev) you did....ignore
#20
Am I not allowed to ask a European member if their country happens to sell export parts for our cars that have long since been discontinued that I wish to have on my U.S. car?!
I don't comment on other threads that members should ignore your comments or those of any others. Please offer me the same courtesy. Thank you.