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Old Jul 2, 2014 | 05:45 PM
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Default '98 Z28 Service

So my Z28 was stored for over 8-10 years after my dad bought it new from the dealer back in 1998. The car currently 15,293 miles as of today. The car is completely stock. & I'm going to do a Service Change (Engine oil, Tranny fluid, Differential fluid, Spark plugs, Oil filter, Fuel filter, etc.) soon.

I want to know which products do you guys highly recommend?
Which oil & fluid ratio, should i use? I live in an area where temperatures are from 80-105 degrees daily.

One more thing, do you guys know where i could get a complete fuel system?
The floater is having some problems, and I just want to buy a new whole fuel system thanks.
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Old Jul 2, 2014 | 06:09 PM
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Don't forget to change the coolant. That should be near the top of your list, IMO. It's well past due.

Oil and oil grade/weight recommendations will vary with opinions. There are several good choices in regards to oil. Personally I prefer Mobil 1 0w40 for LS1s.

One thing important to remember though, as it's a '98 you will want to be sure to use the LSD additive when you change the rear end fluid (I prefer the GM additive myself). '98s still had the Auburn rear that requires this additive. GM also calls for an 80w90 conventional oil for this differential (vs. the 75w90 synthetic for the later Torsen rears).

Spark plugs should be fine if the engine has just sat all these years, but changing them won't hurt anything either.
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Old Jul 2, 2014 | 07:26 PM
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RPM made great points. I'd likely not bother with changing the plugs, but go ahead and pull them to see if they need replaced since you're doing all the other stuff.

For oil, I'd like likely just stick with the OE 5w30 conventional that came in the car. If you want to go synthetic, Corvette LS1's came with Mobil1 5w30. There are plenty of options to go with different weights and formulas, but perhaps just stick with OE for the time being until you can determine what you'd prefer.

You definitely want to stay away from synthetic gear oil in the rear. Stick with conventional back there -- and do not forget the GM limited slip additive.

Here's everything if you want to stick with OE (ACDelco; check Amazon and Rock Auto for best price):

PCV Vlv - CV948C
Oil Filter - PF46
Air Filter - A917C
Fuel Fltr - GF578
Tran Ftr - TF289
Serp Blt - 4K410
A/C Belt - 6K790
Spk Plug - 41-810
Plg Wire - 9748CC
T-stat - 15-10412
Rad. Cap - RC94
Lwr Hose - 20312S
Upr Hose - 26347X
Rear Gasket - 26016661
Lmtd Slip Ad - 1052358
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Old Jul 3, 2014 | 05:30 PM
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Thanks for the info guys, i really appreciate it.
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Old Jul 4, 2014 | 04:18 PM
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Damn....I guess I better change out the REDLINE synthetic 70W90 I have in my 99 WS6?
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Old Jul 4, 2014 | 05:54 PM
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Originally Posted by Striker
Damn....I guess I better change out the REDLINE synthetic 70W90 I have in my 99 WS6?
Synthetic is fine for the '99+ Torsen rear. In fact, synthetic is the recommendation from GM for those differentials. It's only the '98 that has the Auburn rear, and that style of differential calls for conventional only per the GM service manual.

Also, the LSD additive is recommended for all years (per GM), but I really don't see why it would be needed in a Torsen style rear - though it certainly wouldn't hurt to put it in.

Now as for the weight/grade, I have never tried a 70w90 for either differential. The '98s (Auburn) call for 80w90 and the '99+ (Torsen) call for 75w90.
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Old Jul 5, 2014 | 02:57 AM
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Of the car
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Old Jul 5, 2014 | 07:33 AM
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Originally Posted by RPM WS6
Synthetic is fine for the '99+ Torsen rear. In fact, synthetic is the recommendation from GM for those differentials. It's only the '98 that has the Auburn rear, and that style of differential calls for conventional only per the GM service manual.

Also, the LSD additive is recommended for all years (per GM), but I really don't see why it would be needed in a Torsen style rear - though it certainly wouldn't hurt to put it in.

Now as for the weight/grade, I have never tried a 70w90 for either differential. The '98s (Auburn) call for 80w90 and the '99+ (Torsen) call for 75w90.
I gotta double check, but I think that a slightly higher weight wont hurt much....esp when its 5 points.
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Old Jul 5, 2014 | 07:37 AM
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Originally Posted by Striker
I gotta double check, but I think that a slightly higher weight wont hurt much....esp when its 5 points.
I'm running 75w90 in my 98 guess I missed the memo. Also using the LSD trans additive.

For 1998 you will need to replace the fuel pump assembly if you are having any problems. They are only available as full units for $300.

Radiator flush asap, if your car has dexcool I bet that system is rusted out
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Old Jul 5, 2014 | 09:00 AM
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Dexcool is a big piece of shiet. I cannot wait to change mine out. Since I don't drive my car at all, or very little, I plan on putting coolant made for heavy equipment that also spends a lot of time sitting around not driven.
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Old Jul 5, 2014 | 09:37 AM
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Originally Posted by Striker
Dexcool is a big piece of shiet. I cannot wait to change mine out. .

Another for the Dexcool change. 16 years = like stated.
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Old Jul 5, 2014 | 10:06 AM
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My father actually made a good point- he was the one that suggested I change the fluid to the high quality stuff farm equipment uses due to the fact that they stay parked/not started for a long period of time.
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Old Jul 5, 2014 | 10:38 AM
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I've had nothing but Dexcool in my '98 for 16 years. It's been changed regularly, even though the car sits a lot. The entire cooling system is 100% assembly line original with NO leaks or issues at all. The inside of the radiator is clean and there is no gunk in the overflow either.

Dexcool works perfectly fine and won't hurt a thing if you maintain it properly. Change it on time or earlier, don't allow the system to run low or allow any leaks to persist (it doesn't mix well with air), and mix it with distilled water.

There are certain applications were Dexcool has been known to attack gaskets (such as intake gaskets on the 3.8L V6). This is not the case on LS1s. People who have "horror stories" about Dexcool in an LS1 are simply using it wrong (air in the system, going too long between changes, etc.) I've had nothing but [properly maintained] Dexcool in all four of my LS1s, ranging from low mileage garage queens to average mileage daily drivers, and it never caused any issues nor did I ever see any of the cooling system sludge build-up that comes with overly-aged or air-mixed Dexcool.
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Old Jul 5, 2014 | 11:15 AM
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Originally Posted by chrysler kid
I'm running 75w90 in my 98 guess I missed the memo. Also using the LSD trans additive.

For 1998 you will need to replace the fuel pump assembly if you are having any problems. They are only available as full units for $300.

Radiator flush asap, if your car has dexcool I bet that system is rusted out
Where can I get the full fuel assembly? Cause I am currently having problems with the fuel gauge or sending unit I'm not sure..
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Old Jul 5, 2014 | 11:18 AM
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Originally Posted by RPM WS6
I've had nothing but Dexcool in my '98 for 16 years. It's been changed regularly, even though the car sits a lot. The entire cooling system is 100% assembly line original with NO leaks or issues at all. The inside of the radiator is clean and there is no gunk in the overflow either.

Dexcool works perfectly fine and won't hurt a thing if you maintain it properly. Change it on time or earlier, don't allow the system to run low or allow any leaks to persist (it doesn't mix well with air), and mix it with distilled water.

There are certain applications were Dexcool has been known to attack gaskets (such as intake gaskets on the 3.8L V6). This is not the case on LS1s. People who have "horror stories" about Dexcool in an LS1 are simply using it wrong (air in the system, going too long between changes, etc.) I've had nothing but [properly maintained] Dexcool in all four of my LS1s, ranging from low mileage garage queens to average mileage daily drivers, and it never caused any issues nor did I ever see any of the cooling system sludge build-up that comes with overly-aged or air-mixed Dexcool.
How often do you change the coolant?
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Old Jul 5, 2014 | 04:34 PM
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Originally Posted by checo16
How often do you change the coolant?
Depends on the application.

For the garage queen, which sees no more than 500 miles per year at this point, I simply drain and refill the radiator once every two years. This replaces roughly 33% of the coolant each time, and has prevented any issues or sludge from ever developing after all these years.

For the daily drivers, usually a full system flush every 3-5 years depending on usage. They should never be allowed to go past 5 years though...and not even that long if you aren't using distilled water.

At this point, you really need to do a complete system flush (maybe twice) to get everything cleaned up. Then follow a good service routine that suits your usage going forward.
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Old Jul 5, 2014 | 06:46 PM
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Originally Posted by RPM WS6
I've had nothing but Dexcool in my '98 for 16 years. It's been changed regularly, even though the car sits a lot. The entire cooling system is 100% assembly line original with NO leaks or issues at all. The inside of the radiator is clean and there is no gunk in the overflow either.

Dexcool works perfectly fine and won't hurt a thing if you maintain it properly. Change it on time or earlier, don't allow the system to run low or allow any leaks to persist (it doesn't mix well with air), and mix it with distilled water.

There are certain applications were Dexcool has been known to attack gaskets (such as intake gaskets on the 3.8L V6). This is not the case on LS1s. People who have "horror stories" about Dexcool in an LS1 are simply using it wrong (air in the system, going too long between changes, etc.) I've had nothing but [properly maintained] Dexcool in all four of my LS1s, ranging from low mileage garage queens to average mileage daily drivers, and it never caused any issues nor did I ever see any of the cooling system sludge build-up that comes with overly-aged or air-mixed Dexcool.
THANK YOU!!

Same here, with 170K+ miles.

I do change mine out with a full cleaner flush every 2-3 years, and I use Zerex, which I am told is even better than the original factory, Texaco made Dex Cool, and it has never run low or been run with much air in the system.
Dex Cool also does not like being used in mixtures of much less than 50/50, that is, much more water than coolant.

The ONLY times I have had any sludge or gunk in the system is when I used the Red Line GAS ENGINE Water Wetter (red stuff, the blue diesel W.W. is FINE), and when the factory p.s. cooler was leaking into the upper radiator hose.
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Old Jul 5, 2014 | 08:27 PM
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Originally Posted by dailydriver
THANK YOU!!

Same here, with 170K+ miles.

I do change mine out with a full cleaner flush every 2-3 years, and I use Zerex, which I am told is even better than the original factory, Texaco made Dex Cool, and it has never run low or been run with much air in the system.
Dex Cool also does not like being used in mixtures of much less than 50/50, that is, much more water than coolant.

The ONLY times I have had any sludge or gunk in the system is when I used the Red Line GAS ENGINE Water Wetter (red stuff, the blue diesel W.W. is FINE), and when the factory p.s. cooler was leaking into the upper radiator hose.
Yeah dexcool is fine as long as it doesn't sit. You start getting some sludge and it'll seize the water pump. Especially in a car that has set for over a year

The 1998 fuel pump assembly can be found on rockauto.com or special ordered at all major auto part stores

I ment to respond to your thread but youre in a canadian or export version fbody. Can't view your video on my phone but a Chevrolet dealer should also be able to get one aswell
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Old Jul 5, 2014 | 10:23 PM
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Originally Posted by chrysler kid
Yeah dexcool is fine as long as it doesn't sit. You start getting some sludge and it'll seize the water pump. Especially in a car that has set for over a year

The 1998 fuel pump assembly can be found on rockauto.com or special ordered at all major auto part stores

I ment to respond to your thread but youre in a canadian or export version fbody. Can't view your video on my phone but a Chevrolet dealer should also be able to get one aswell
Yeah my dad bought the car new in Mexico...
& When you have time, give the video a look through a computer and lemme know what you think is wrong with the fuel gauge or if it's something else.

Here's the car itself, SGM.
http://s34.photobucket.com/user/chec...d28b5.jpg.html
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Old Jul 6, 2014 | 03:57 AM
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Originally Posted by chrysler kid
Yeah dexcool is fine as long as it doesn't sit. You start getting some sludge and it'll seize the water pump. Especially in a car that has set for over a year
Sitting won't cause any issues with Dexcool at all, unless the coolant is past its service life or there has been a system leak causing low coolant level/excessive air contamination prior to storage.
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