need advice for a tuneup

[OKCSuburban]

I have a 2000 Suburban, 5.3 motor, 4 wheel drive with 92000 miles and it runs poorly when it has sat for a while (1 week or so.) This is our vacation vehicle and it is not driven every day.

I was thinking of replacing the plugs and airfilter. Can I use the Bosch Plat 4 plugs. Will it run as good as it did with the factory plugs? It normally runs great and very smooth. I have tried to gap plugs in the past with little success, this is one reason I like the Plat-4 plugs.

Airfilter K&N seems to make a good product. Martel Brothers has a reasonable price. Is this type of filter good?

We just replaced the drive belts. Should we of replaced the tension pullie? What type of noise should we be aware of?

I did notice a faint tapping noise on the bottom side of the engine but could not hear it on the top side while test running after putting on the drive belts. Am I getting a serious warning here?

Oil Changes are done every 5k with Mobile 1 oil, 10w30 is what I have used for many years now. Oil pressure seems to be the same as when it was new according to the gauge. I normally do all oil-filter-lube at home because I caught a tech just putting grease on the top of the a-frames during an oil change.

How about the water pump and hoses, no fluid leaks noticable. Last summer we did have to add about 1/2 gallon of Antifreeze (premix prestone) while on a trip as the low coolant light flashed.
How long will these water pumps last.

Small thunk noise/feel in the steering, I was told the dealer now has a fix for that but have not scheduled it in yet. Anyone know of this fix?

All other fluids were changed last year at the dealer. Front and rear dif, transfer case, transmission, the fuel regulator, and fuel filter.
Other replaced parts: Idler arm, rf outer tie rod end, front shocks, battery, I think that is it.

This has been a very good vehicle.
The best MPG I have ever had with this truck is 18.5, once coming back from Colorado and once going to Houston.

My goal here is to have a safe and fun summer vacation with my beautiful wife and great children... We would like to keep and drive this Suburban for another 5 years. The only rattles are my kids toys.

[suburban_lee]

92K miles - you're still breaking her in!

Is there any reason besides gapping that you are looking for an alternative to the AC-Delco plugs that are OEM for your burb? I've heard mixed opinions on the Bosch. I've used the platinums in my last Suburban, but the best performance the I've gotten has been from the OEMs. Just my two cents on that, I'm sure I'll have some disagreement out there. Certainly, when you get to the ignition wires, distributer cap and rotor, I strongly recommend AC-Delco and nothing else. As for the air filter, I've never really had much of a preference myself.

Ther real reason I replied was to address your coolant leak question and your steering question. My current burb was losing a very small amount of coolant - the the effect that I had to add a quart or so every few months. While chasing down a misfire problem, we found the coolant leak to be in the intake manifold gaskets. Even still, no spark plugs showed signs of fouling. Keep this in mind, unless you're actually leaking around the pump.

The steering - if the problem is that it's feels tight, as if it's stuck, then suddenly frees itself (I'm trying to interperet klunk feel), then your problem is most likely an electronic part at the bottom end of the steering column - I believe it is called a steering position sensor. This is part of the speed controlled steering system, and apparently it is a common problem - or was. I replaced it myself and the part was around $60, dealer only. Not a difficult job if you are mechanically inclined enough. I think if you searched these forums, you'd find a post with the specific replacement instructions.

[010175]

I agree with the above post. I was told that if you have water leaking (head gasket) inside your engine you might not see it in your oil. I was told you could get the oil tested for water and antifreeze to see if your headgaset is leaking. I have a 1999 and at 75,000 miles the head gasket was leaking as I saw water leaking from the back left side of the engine. Now at 150,000 it was on the rack being tested for rear end problem when the shop (Pro-Gear San Diego) had me listen to the knocking from the bottom of the engine. Check my piston knocking or piston slap. I changed oil and cannot hear the knock now. I hope this information helps. Dave

[OKCSuburban]

Good info here.
Might be time to move up to a little thicker oil.
The water useage has been little to none since last summer. I have not added any since then. I will keep an eye on it.
The plugs, well I have been running the plat 4's in my BMW and they have done great. The factory plugs have done great in the suburban so maybe I should go back with them.
The steering, I notice a clunk and sometimes it does feel like it is stuck. I might have more than one part going out or showing wear. This will take more study.
Thanks for the info.

[Eggert]

Hi, K+N replacement air filters are good. I use the OEM ones. The tension pulley does not usually get replaced with the belts.
The GMC Service Manual says:
Recommended oil viscosity is SAE 5W-30.
Spark Plugs - Denso:PTJ16R15 (GAP 1.52 mm, 0.060 in)
Take care, Eggert

[SpitAndDirt]

Ditto on the use of stock OEM plugs and K+N filter with stock air box setup. I use Mobil 1 synthetic 5w-30 with 163,000 miles now.

[OKCSuburban]

Do anyone forsee any problems switching back to the 5w30. I thought I was providing extra protection by using the 10w30. We also pull a boat, it weighs in at 4000 to 4500 fully loaded. Not too often but many times when we do it is for a 200 mile pull each way.
If I could get a little better MPG that would be great.?
Anyway since I have been using 10w30 for several years now I just want to make sure switching back would not be a problem.

[Eggert]

Hi, please do switch back soon.
You just cut out the thinner part of the range and lost protection for tight engine tolerances, where the thicker oil can not reach.
I am towing a 10,000lbs+ camper through mountainous New England and have had no problem with the Mobil1 15W-30.
And by the way, you lose any right to gas mileage when you start towing...
I get 6 to 7.5, depending on the hills.
There is only one efficient fuel to air ratio. More power means more gas.
Free flow this and that only lets more air in so you can burn more gas to get more power. A little more air and gas with an air filter and exhaust, lots of more air and gas with a supercharger.
Better mpg means using less gas, less power, smaller engine, lower rear end gear ratio, slower turning engine.
Take care, Eggert

[maheath]

FYI, I changed the plugs on my 2000 Suburban a couple of months ago and the originals were not AC/Delco. They were Denso plugs and I've owned it since brand new.

I put in AC/Delco plugs and they seem to be fine. The plugs specified in my owner's manual have been superceded.

Also, if you choose to replace the plug wires, there are two versions. The easiest way to distinguish them is to measure their length.

[gregory914]

I too swear by Mobil 1, and have only used 5w30 since new. I now have 119K miles and no problems other than the typical cold start piton slap that has been there from day one (no worse, no better), and I'm also an advocate of K&N filters.

When it comes to tune up parts, I was told to stay with AC Delco. I'm curious if the Denso plugs were factory, cause they are the latest big deal for hi-performance imports. My son has a VW GTI with the VR6 engine and put a supercharger on it last fall. Part of the new "required items" were Denso plugs of a certain heat range to go along with the bigger injectors, modified oil pan (oil return line from blower) and a newly burned chip. At 9 PSI it turns 13 second quarter mile times @ 105mph.

My question is should I try the Denso plugs or stay with the AC Delco ones ? I plan on doing a complete tune up soon with plugs, wires, cap and rotor all AC Delco or maybe the Denso plugs.

Any advice?

THANKS!

[Eggert]

Gregory,
yes, the Denso plugs are factory.
What I posted above is from the 2001 GM service manual.
They say Denso.
That does not mean that AC Delco are bad.
It just means GM puts Denso in it.
I just do what they say, as they designed it.
There was a time when you were OK as long as you had the right heat range and you could cross-reference between brands.
Maybe you still can, I would just not bother, if they say Denso then that is good enough for me.
Take care, Eggert

[gregory914]

Thanks Eggert, mine has ACs but I'm going to try the Densos. In another 119K miles I'll report back on how they worked, or if they don't, when I went back to ACs.

[OKCSuburban]

I had to get into my owners manual the other day and noticed the oil recomended was 5w30 with 10w30 as an optional oil weight as long as you stay over 0 degrees (f).
My suburban stays inside at night and during the winter my garage stays warm (above 35) according to my thermometer. This is a trip vehicle for us and with children we travel in the summer for most of our trips.
Most of our travels are southward, esp in the winter. During the summer we pull a boat (3500 to 4500 pounds). Also most trips are to the gulf coast.
Mileage with this vehicle: the best we have gotten was just over 18.5. I found 2 times with this mileage.

2000 Suburban (new body style)
LT with barn doors
5.3 motor 4 wheel drive
Current Mileage is 93000.
quite on start up? I do not notice a knock. Sometimes she will sit for a week or more between drivings.