Dealer Recommended Services... Bs?

[cwtillson]

Hello, all. I've got an 08 Yukon Denali with 53,000 on it. Just got back from a full synthetic oil change from the dealer and they sent me home with a laundry list of recommended maint items. I bounced these off of my owners' manual and found a few discrepancies.

 

1. Brake System flush- never heard of this one before, not in manual, can't see dropping $100 on it.

 

2. Auto Trans Fluid/Filter change- dealer says @ 50,000, but the manual says thats only if you do alot of towing or hard driving. I think I'll wait until 100K

 

3. Transfer case fluid- This one they actually agree on! Supposed to be at 50K, so I'll probably get that done soon.

 

4. Clean throttle body/fuel injection service- not in manual at all. I use a bottle of fuel injector cleaner added to my gas tank every so often. I'm calling BS on this one.

 

5. Front and Rear Differential Service- Again, no mention of this one in the owners' manual at all. At this point, we do virtually no towing with this vehicle... it's basically just a warrior of the suburbs! I am in Chicago, so we see a little snow here and there, but otherwise the vehicle isn't abused whatsoever. Dealer wants me to fork over $400 for this one.

 

Anyone who can help me on this, I would certainly appreciate it! I love this truck and want to keep it for a very long time, but I also know how sleezy lots of dealers can be, and the service dept is no exception.

 

Thanks very much in advance!

[Fobroader]

Front and rear diffs, you can do at home in the garage in about an hour with some axle lube and a cheap transfer pump.

T-case, same thing as differentials, get the right fluid and transfer pump.

Throttle body, take intake hose off, spray some throttle body cleaner in there, put hose back on.

Brake fluid flush, how dark is your brake fluid??? if its black, yes, if not, dont bother.

Auto tranny, Id reccomend getting it flushed and having the fluid replaced every 50K, cheaper than a tranny rebuild.

[dlstewart01]

Brake fluid is hygroscopic, it attracts and absorbs water, I change mine every couple of years.

 

I change my trans fluid and filter every 30,000 miles. never had a failure.

 

I change the diff fluid out early, then every couple of years. never had a failure.

[Z45]

The dealer will always recommend unneeded services. Its easy money for them.

 

Monday, May 16, 2011

Dealer Profits Up

One benefit of the record number (nearly 3,000) of dealerships forced to close their doors in recent years is that profits at those dealerships that survived are the highest they've been since 1986, according to this article (subscription required) from Automotive News.

 

The same article also notes that service sales now account for 59.6 percent of revenue, up from 51.9 percent in 2007.

[05GMCZ71]

1. Brake System flush- never heard of this one before, not in manual, can't see dropping $100 on it.

**This should certainly be done once every few years, and always when you have your brake system worked on**

 

2. Auto Trans Fluid/Filter change- dealer says @ 50,000, but the manual says thats only if you do alot of towing or hard driving. I think I'll wait until 100K

**If you plan on keeping this vehicle past 100k then you should change it at 50K. I do mine every 30K. The Transmission is one of the weakest points on the vehicle and doing preventative maintenance now will save you in the long run.**

 

3. Transfer case fluid- This one they actually agree on! Supposed to be at 50K, so I'll probably get that done soon.

**I do mine every 30,000 miles or every 2 years since my 4X4 system gets a good workout in the winters**

 

4. Clean throttle body/fuel injection service- not in manual at all. I use a bottle of fuel injector cleaner added to my gas tank every so often. I'm calling BS on this one.

**You should be fine AS LONG as you are using a Top Tier fuel. Filling up at your local Walmart or mom & pop gas station and then throwing in a bottle of fuel cleaner every so often is NOT ENOUGH to keep the fuel system clean, Top Tier fuels have additives in them to keep the fuel system clean.**

 

5. Front and Rear Differential Service- Again, no mention of this one in the owners' manual at all. At this point, we do virtually no towing with this vehicle... it's basically just a warrior of the suburbs! I am in Chicago, so we see a little snow here and there, but otherwise the vehicle isn't abused whatsoever. Dealer wants me to fork over $400 for this one.

**That price is way out of line. The Diffs needs to be serviced every 30,000 to 50,000 miles EVEN IF you don't tow or use 4WD all that often.**

[05GMCZ71]

FYI the only fluid that is safe for 100,000 miles per GM is the Death Cool (DexCool) Coolant. And I would not wait 100,000 miles on that myself. I have mine changed every 2-3 years and tested yearly.

[Doug_Scott]

First thing to do is find a service place you can trust. Talk to your friends/relatives, get recomendations from people you actually know and trust.

As for what the manual recommends, no one fits in the lower level of use. In other words, always take the heavy use recommendations. Those short trips with no abuse are actually not good for the vehicle. Fluids don't get up to proper temps. Condensation accumulates in the oils. That is not good.

 

It is always going to be cheaper to do it yourself, but some people just do not have the ability or tools or location to work on their own vehicles.

 

Sometimes the dealer recommended work is something they have found to be useful in your area. For example, the owners manual does not take living in San Fransisco and always driving in those hills. Dealers in those areas know what those hills do and how they affect cars and trucks in the area.

[redjewel2ss]

i agree with a lot of these guys.

 

of course, changing the engine oil when the oil life indicator is at or below 25% is good maintenance. changing the transmission fluid and filter every 50,000 is good maintenance. changing the transfer case and axle fluid every 25,000 miles is good maintenance. coolant fluid change every 100,000 miles is good maintenance.

 

brake fluid all depends on the condition of the braking system. look at the fluid in the brake cylinder, if it is as black as used motor oil, bleed the brakes and change it. same with the power steering fluid.

 

when the dealership wants to charge you a lot for a fuel/air system clean, all they do is hook up a hose directly to the fuel rails and pump some cleaner in. then clean off the throttle body blades. you can easily do this at home and even take it a step further. go get some seafoam spray and follow the instructions on the bottle on how to clean the inside of your intake manifold. this will clean any oil blow by out of the intake manifold as well as the throttle body blades. for the fuel system, i prefer Lucas Upper Cylinder Lubricant or if you know a buddy at a shop that uses BG products, do that. BG makes some great products for cleaning the inside of your motor. i do this to all my cars every 25,000 miles.

[ujtruck]

if you have $$$ do them, always good to change fluid - but Brake System flush - nnaah - not yet!!!

[Black02Silverado]

1. Brake System flush- never heard of this one before, not in manual, can't see dropping $100 on it.

Like snakedoctor stated, the fluid is hygroscopic, how important are your brakes to you?

 

2. Auto Trans Fluid/Filter change- dealer says @ 50,000, but the manual says thats only if you do alot of towing or hard driving. I think I'll wait until 100K Again, if you plan on keeping this vehicle I would get it done. Every 50k is a good figure to go by.

 

4. Clean throttle body/fuel injection service- not in manual at all. I use a bottle of fuel injector cleaner added to my gas tank every so often. I'm calling BS on this one. Get fuel from a gas station that has a high turnover, this means fresh fuel so you shouldn't have any problems.

 

5. Front and Rear Differential Service- Again, no mention of this one in the owners' manual at all. At this point, we do virtually no towing with this vehicle... it's basically just a warrior of the suburbs! I am in Chicago, so we see a little snow here and there, but otherwise the vehicle isn't abused whatsoever. Dealer wants me to fork over $400 for this one. This can be argued forever since most never mess with their differentials and vehicles go into 300k miles like that with no issues. Does it mean it is good for the diff's? I would say not. Diff fluid change out with a good quality synthetic every 50k is a good idea. You don't tow but your rear axle gets a good workout in the winter time with all that snow.

[Rons05z71]

I think the prices are out of line, If you cant do it yourself try some other places or shop around a bit. Sometimes going to one of those in and out places can be ok if they are good. On the brake fluid I like just sucking what is in the resivoir out and refilling, then when I do my brakes and I bleed them I add some more fluid,I consider this just as good as total flush.

ALot of people talk about flushing the tranny, I have heard bad things about this as it loosens junk in your tranny up and then cloggs the valves, I prefer dropping the pan and changing the filter and refilling the fluid.

[GMTech686]

Everytime the throttle body is cleaned a throttle/idle relearn needs to be performed. It's done with a Tech 2.

[tanked_darren]

Hello, all. I've got an 08 Yukon Denali with 53,000 on it. Just got back from a full synthetic oil change from the dealer and they sent me home with a laundry list of recommended maint items. I bounced these off of my owners' manual and found a few discrepancies.

 

1. Brake System flush- never heard of this one before, not in manual, can't see dropping $100 on it.

 

2. Auto Trans Fluid/Filter change- dealer says @ 50,000, but the manual says thats only if you do alot of towing or hard driving. I think I'll wait until 100K

 

3. Transfer case fluid- This one they actually agree on! Supposed to be at 50K, so I'll probably get that done soon.

 

4. Clean throttle body/fuel injection service- not in manual at all. I use a bottle of fuel injector cleaner added to my gas tank every so often. I'm calling BS on this one.

 

5. Front and Rear Differential Service- Again, no mention of this one in the owners' manual at all. At this point, we do virtually no towing with this vehicle... it's basically just a warrior of the suburbs! I am in Chicago, so we see a little snow here and there, but otherwise the vehicle isn't abused whatsoever. Dealer wants me to fork over $400 for this one.

 

Anyone who can help me on this, I would certainly appreciate it! I love this truck and want to keep it for a very long time, but I also know how sleezy lots of dealers can be, and the service dept is no exception.

 

Thanks very much in advance!

Pretty much sums it up. I would do the diffs when you do the transmission though. Brake fluid and throttle body service are not needed. I don't know anyone who does these.

[8.1HD/ALLISON]

Throttle body cleans are very common. Sooner or later it will gum up, throttle plate will start sticking, will throw a check engine light, could go into reduced power mode if bad enough and leave you limping down the road. My theory in general, if you are going to keep something a while you should take care of it. Preventive maintenance is always cheaper than repair bills.

[Doug_Scott]

Brake fluid flush and refill has been around longer than I have been a mechanic (coming up on 35 years). Chances are that anyone that has had calipers rebuilt or wheel cylinders rebuilt/replaced has had a flush and fill done on the brake fluid and most likely did not even know it was done. With the ABS in there, it is more important than ever.

 

This will be long...

 

Brakes on most vehicles have been getting smaller and smaller in the race to reduce weight. Those smaller brakes have to handle a lot of heat. What manufacturers sort of forgot was that it takes a certain amount of heat to stop a vehicle. If the weght stays the same, and brakes get smaller, they have to be able to generate as much heat as the larger brakes did. They also have to dissapate that heat with less area to do it in. The brake fluid gets hotter, and stays hotter longer. If you have any moisture being suspended in the fluid, and get the fluid to its boiling pressure, the moisture becomes steam. Keep in mind that anytime you pressurize something, the boiling point increases, and anytime you contaminate something the boiling point changes, if the contaminate has a lower boiling point, it will reduce the boiling point of the other fluid. DOT 4 has a boiling point of about 450 degrees F. If you contaminate it to the point of 3.7% water by volume, the boiling point is now 311 degrees F. If you are applying the brakes the boiling point is higher, right up to the point that you release the brakes. Now that very hot fluid will boil the water out of it instantly. If you are in the 3.7% water by volume range, you now have a very spongy pedal.

 

You can go by the colour of the fluid in the resevoir, but, keep in mind that fluid in the resevoir is a very long ways from the fluid in the caliper, and is not a good indicator of fluid condition. The amount of fluid movement in the lines when you apply the brakes is not very far in the grand scheme of things. I would guess it moves about 8 to 12 inches for the rear brakes (assuming they are correctly adjusted). Those steel lines are about 12 feet long, and 1/4 inch in diameter. How do you expect the fluid in the master to ever get to the line going from the front to the rear of the vehicle.

 

Brake fluid will pull moisture through the flex hose. I don't know how it does it, but, from what I have read over the years, all state that moisture will be absorbed through the flex hose in the right conditions, yet not leak a drop of brake fluid.

 

Sorry for the long read, but, brake fluid is about the most abused service item there is.