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95 Caprice L99 tune up questions

5K views 16 replies 9 participants last post by  95capwagon 
#1 ·
So my bubble just cracked 100K. I have put 19K since buying last February, and once my taxes come in its getting tuned up. Gonna do the 100K trans and rear fluid change, but need input on a good quality set of plugs and wires. I drive this car for pizza delivery 5 days a week, averaging 400-500 miles/week. Whats out there that will help me in way of fuel economy and engine preformance?

Phil
 
#2 ·
MSD wires and AC Delco DP's. Uses the same as the LT1. I would also consider Injector replacement too after 100K....shameless plug for me. Just so happens that I have a set of Accell 19 lb injectors with about 10K on them that I had in my L99 before going to the LT1. Cost me $300 from Summit, $50 for the set if you want them.
 
#6 ·
Injectors



Just checking back and wanted to give you a heads up if you're still interested. I just posted these up in the "For Sale" section.

http://www.impalassforum.com/vBulletin/showthread.php?t=268577

But you got 1st dibs if you still want them. If you can't do it all now, just give me a deposit ($20?) and I can hold them for you...my "lay-a-way" program :>) I'm sure we could work something out on timing.

BTW - How far are you from Elkton, Md.? Maybe we could meet up instead of ship.
 
#9 ·
Here's my feeling on the injectors for the L99. My car has 254,000 miles on it. The original injectors have never been out of it. Every once in a while, I run a tank or two of premium through it to clean it out, preferably when I am going on a longer trip. Works great. I stuck a borescope down it's throat a while back and the injectors look very nice down in there. So, that being said, I don't feel that new injectors or having mine cleaned would be of any benefit to me.

Now, as for the rest of your tune-up, so to speak. Remove water pump and replace with a new one. The input shaft seal will start to leak soon, if it isn't already, draining coolant onto the opti-spark. Change the cap and rotor on the opti. Get a Delphi cap and rotor kit. You will need a E-4 inverted torx socket to do it. Also, with the water pump, change the hoses(all of them), and t-fitting and restrictor. Drain all of the coolant and flush the block. Get down underneath and remove the knock sensors on both sides when you do this, as it is the only way to completely flush the block. Refill the system with new coolant and destilled water. Check condition of airfilter, and replace as necessary. Cold air kits are not a bad thing. I installed a K&N kit a long time ago, and it netted me an almost 2 mpg on the highway increase in milage. Change the PCV valve. It's on the driver's side of the intake manifold. Change the serpentine belt. Change trans fluid. Change Diff fluid. Grease chassis. Change oil, if due. Previously mentioned spark plugs. Wires, maybe? I changed mine the first time, but not the second time, 40K miles ago.

Thats my .02, and it has worked well for me, at least so far. I'm half way through my second tune up's service life so far and I'm still running great.
 
#10 ·
"It's common knowledge that Injectors get dirty, clogged and lose their ability to perform. Especially after 100K miles and should be professionally cleaned or replaced. "

Not to question your motives, but you are trying to sell this new guy something you are trying to unload. I have 280,000+ mi on my LT1 and it still has the original injectors. So much for common knowledge. Run some Techron through it once in a while either via a tankful of Chevron or a bottle of the straight stuff.

Putting a CAI is another waste. He is trying to save fuel, not gain HP or the rushing sound that is the reason most people do this mod. The stock intake is not restrictive, especially on a L99. Inducing cold air is for the purpose of increasing density of the mixture. The reason the factory doesn't do this is to maximize fuel economy. If they could figure out how to get one more MPG out of the design, they would. Stories of increased fuel economy with a CAI cannot be supported with hard data.

This guy is delivering pizzas and trying to save money. 100,000 is barely broken in on these cars. You don't need a cap and rotor at this mileage either or a water pump. Just do the things that I and the other posters who have recommended just a few relatively modest maintenance items and enjoy your car. Make sure your opti vent harness is working by checking vacuum. You will be fine. Don't waste money doing anything that departs from stock.
 
#11 · (Edited)
"It's common knowledge that Injectors get dirty, clogged and lose their ability to perform. Especially after 100K miles and should be professionally cleaned or replaced. "

Not to question your motives, but you are trying to sell this new guy something you are trying to unload. I have 280,000+ mi on my LT1 and it still has the original injectors. So much for common knowledge. Run some Techron through it once in a while either via a tankful of Chevron or a bottle of the straight stuff.

QUOTE]

Uhhhh....Yes, I feel like you are questioning my motives. When you say I'm "trying to unload" these parts on him, I take offense to that. I was pretty upfront with what my intentions were when I offered these up. I'm not making him buy anything nor could I. What I offered was advice based on what I experienced and had parts that I could no longer use and thought they may help him. If it helps him out, great. He can choose to buy these if he wants to. But I take it personally when you try to question my motives here. If you got a bug up your arse because of this or how I put things, then I hope it does not cause you indigestion.

What worked for you is great and I can only indicate what worked for me. But I will never say that if I got 200K on something that everyone else should too. As great as these cars are, every car if different and has different needs. Just becuase I chose to purchase $300 injectors and other bolt-ons for the L99 over the years might be considered a waste of money by some, I can live with that. But don't question my motives with trying to sell those and possibly help out another member. I always try to offer help here when I can and don't ask for anything in return.

To the original poster - Choose to do what you think is best for your build. I never meant to make it sound like you should do new injectors and only you can determine that. I have ran the L99 for years and found it to be a great little motor. I did a few bolt-ons to it and can offer advice if you need it with no obligation to buy anything :) I also swapped it out for an LT1 and can let you know what may be needed there if you decide to go that route. Again, no obligation to buy anything...except maybe a beer if we ever meet. Take care.

EDIT - Hey Phil - Do your reasearch and check just this 1 link I found by Googleing "should I replace my fuel injectors". http://ezinearticles.com/?Fuel-Injectors:-Time-To-Replace?&id=63453 Just because some may have them for a while, does not mean they shouldn't be replaced or that they don't lose effeciency. It also does not mean you can't get another 100K out of them. But if YOU decide to do this, do your research and don't just look at mine. Look at a new set from Summit or any other manufacturer and also look at getting a service to clean yours. I was happy with these units from Accell. You may also do well with just swapping the fuel filter and adding some injector cleaner to the tank for a few fill-ups. Also consider cleaning the Throttle body as they can get pretty gummed up, especially after 100K. I pulled my TB off the car to clean it real well and added a filter/breather to the valve cover so the hose going into the TB was at least filtered. Over time this has really helped keep the current TB clean.
 
#13 ·
I fear I may have inadvertently caused an argument. I had my pops pull an injector on either side and check them for me, and assured me at most they only need a lite cleaning. As soon as my taxes are deposited I will be getting my plugs/wires & air filter. Changed the serpentine at 98k along with the pcv valve. Still contemplating changing the coolant temp sensor since I'll be in there anyway, definitely want to change the thermostat and radiator hoses. Does anyone know if the thermostat housing takes a gasket? I had noticed awhile back a couple tiny drops of coolant at the seem but a little smear of silicone gasket maker took care of that. The biggest thing I need to fix is the ghetto rigged fans. Previous owner ran the power wires straight to the fuse box under the hood.

 
#14 · (Edited)
I fear I may have inadvertently caused an argument. I had my pops pull an injector on either side and check them for me, and assured me at most they only need a lite cleaning. As soon as my taxes are deposited I will be getting my plugs/wires & air filter. Changed the serpentine at 98k along with the pcv valve. Still contemplating changing the coolant temp sensor since I'll be in there anyway, definitely want to change the thermostat and radiator hoses. Does anyone know if the thermostat housing takes a gasket? I had noticed awhile back a couple tiny drops of coolant at the seem but a little smear of silicone gasket maker took care of that. The biggest thing I need to fix is the ghetto rigged fans. Previous owner ran the power wires straight to the fuse box under the hood.
Nah, don't worry about it, I'm just glad to hear you can get them cleaned.

But do get those wires for the fans fixed up. That is not a good way to hook up wires and looks like crap. Looks like someone might have been in a hurry.

On the Thermastat housing....there is a rubber o-ring for the gasket. They seal up pretty well with no need for RTV as long as the other surfaces are clean and smooth. Be carful not to torque the 2 bolts too tight as these are pretty small in an aluminum intake.

When you go to drain the coolant, here is what I did - After draining the radiator, I.pulled the bottom heater hose off the waterpump and held a Drywall Mud pan (12") under that fitting/hose. It's square/narrow and fits under there pretty well. May not be a bad idea to cover the Opti with foil or something just in case. But doing this I did not spill any coolant on the floor. Then you can pull the knock sensors in the block to drain the rest....that is a little more messy. Be sure to bleed the system properly and consider getting a Bleeder valve that someone sells here. No, not trying to make you buy something you don't need :) but it does make the process much easier than using the stock bleeder and you can run a hose down past the opti so it doesn't get wet.

EDIT - I would assume you would do this anyway, but while the housing is off, replace the thermastat. It's a $5-$10 part and good insurance.
 
#15 ·
As far as the tune-up goes for 100k, my recommendation is this...

AC Delco Platinum Plugs - Always gap to specification!
A good set of performance wires (better insulation & more efficient spark) - Variety of brands available
New PCV valve
Clean MAF with the proper MAF cleaner spray you can get at any parts house
replace air filter if you haven't done so already
fuel filter
check vacuum lines - replace as needed

That should keep your engine running at optimum efficiency

If you haven't changed your transmission filter yet, check the fluid dipstick and verify that your transmission fluid is still "red" and NOT "Orange". If it's still "red" I'd recommend getting the transmission flushed and getting the filter changed.

Definitely get the differential fluid changed if you haven't done so already.

As far as your fans go, Upgrade the grounds on those fans!!! I can't stress that enough.
The main reason most of these cars have had fan harnesses short out is because the factory ground for the fans are not strong enough. When this happened to me, I re-wired the entire fan harness all the way to the fuse box (with a higher gauge wire) and made new grounds for each fan. With the new fan wires, I by-passed that big Grey plug the original harness plugs into. I also routed the new ground wires to where the battery grounds to the inner fender wall next to the battery. I've never had that problem again. And I've put over 120k miles on my car since I did that upgrade. It will take a couple of hours to do with the proper connectors, but well worth the upgrade. I got the replacement connectors/pins for the fan motors and fuse box at innovativewiring.com.

Good luck with everything and I hope this information was helpful.

-TheImpalaMan
 
#16 · (Edited)
Well, works been slow this morning so I have been under the hood. Trans fluid is full and nice clean red color. Been trying to figure out my washer fluid problem, I had to refill it awhile back and now it doesnt spray, thinking I need to pull the probe thing out the bottle and clean it. I had checked out that relay/wire kit on that site, havent made up my mind yet as I dont know that I can do the job myself, and if I mess up Im screwed as I only have one car.

What type of gear lube should I be running and how much? If I remember right I have 2.93 gears in the rear.

A little off topic but can I change out the center link/tie rods with hand tools or does it need an impact gun? I know it will need tobe aligned but any bit of money I can save doing the work myself makes a lot of difference.
 
#17 ·
It is good to hear from a few others in the "high" mileage club. I changed the opti, water pump, wires, plugs and hoses as a preventative measure at 100k. I haven't touched them since. I have replaced the cruise control servo, two sets of shocks, two pairs of mufflers, multiple sway bar end links, a couple of radiators, several sets of tires and too many Silverstar headlamps to think about.

Brakes and tires last longer than any of my front wheel drive cars. I have never replaced a fuel pump, but I never let it run below an (indicated) 1/4 tank. I don't have to add any oil between changes.

The moral: don't buy into the hype of replacing parts unnecessarily. Keep an eye (and ear) out for problems. Change the oil every 5k with quality dino. Treat the trans to an occasional drain and fill. Work your way through all your current problems (fan wiring) and the known issues, most of which have inexpensive solutions: exhaust manifold bolts, fuel pump relay, and the like. I have driven my wagon over 260k, and I have never been stranded for a mechanical issue. Only flat tires.

I have a thermostat housing o-ring I would be pleased to contribute to your efforts. PM me your address, and I'll mail it out.

Good luck!
 
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