The "Ask a Mechanic" Thread (merged)

[SpringfieldSkins]

OK, so first off, I'm not a mechanic. I am a Service Advisor, and I've been doing this for the last 7 years. If I titled this thread "Ask a Service Advisor", people might not actually pick up what I was referring to. For those of you who do not know what a Service Advisor is, I'm the guy who talks to you when you bring your car into the shop. I am the liason between the Mechanic and the customer. My job entails me being knowledgable about cars and trucks of all models as well as being able to well communicate with the customer what is going on with their vehicle.


I started this thread because there are many questions and misconceptions about vehicles in this day and age. Many people think they know exactly what they are talking about when it comes to cars, but as technologies change, sometimes what was once right isn't correct anymore. There are some people on here who really do know what they are talking about and you guys should chime in too.


I intend on this being an educational exercise for those of you here on ES who know nothing about how cars work, have a problem or just want to ask a question. I plan on answering any questions with a response that would actually educate you about the question you asked, basically explaining it in layman's terms.


So, there we go. Let's see how my little foray into public service turns out.

[zoony]

2 questions... is the fuel injector service bs? especially if you've been using Techron every 5k or so?

Also, talk to me about changing coolant. Honda manual says 100k... Honda dealer told me 50k. Dealer claims manual is BS, written to satisfy the EPA. WTF. (they also said the same about transmission fluid intervals, etc.)

also, tell me about radiator flushes

[skinfan2k]

I have alot of paint chips on my car and was thinking about getting it repainted cuz its not that great lookin on the hood. My current paint is pearl or 2 tone? Some are suggesting me to just use the regular paint which doesn't allow for a shadow and what not? Any suggestions

[twa]

Why do you try to sell extra services?

[twa]

I have alot of paint chips on my car and was thinking about getting it repainted cuz its not that great lookin on the hood. My current paint is pearl or 2 tone? Some are suggesting me to just use the regular paint which doesn't allow for a shadow and what not? Any suggestions

Do you think the pearl is worth the extra price?

If so get it,if not go plain.

I hate customers that don't know what they want...can ya tell?

[mikered30]

How do you clean a drive by wire throttle body? I am afraid to touch the butterfly valve with anything.

[dfitzo53]

Should you engage the parking break on an automatic even on level ground? If so, should you do it while the car is in drive/reverse, or in park?

I've heard all different things on that subject.

[SpringfieldSkins]

2 questions... is the fuel injector service bs? especially if you've been using Techron every 5k or so?

Also, talk to me about changing coolant. Honda manual says 100k... Honda dealer told me 50k. Dealer claims manual is BS, written to satisfy the EPA. WTF. (they also said the same about transmission fluid intervals, etc.)

also, tell me about radiator flushes

1. No. Techron (I assume that is a fuel additive you add to your tank) may help a little. A complete fuel induction service can be very beneficial to both engine performance and fuel economy. Over the life of your vehicle, carbon will build up everywhere that air flows (from at the throttle body all the way through the combustion chamber). Carbon will build up on the throttle body, in the vacuum lines, in the intake manifold, and on the valves and piston tops. This build up of carbon will in effect, lessen the breathing quality of the engine. The ECM (car's computer) will mask this by adjusting fuel trim and the idle air control (a small valve that bypasses the throttle plate). A fuel induction service, if performed correctly, will clear all or most of this carbon out resulting in a better breathing engine meaning better fuel economy and engine performance.

This doesn't mean your car needs it every 5K miles, more like every 30-45K miles. Pulling off the air snorkel and looking at the throttle plate can tell you a lot as well as looking at scan tool data on fuel trim and idle air control steps. If your fuel trim is far out of the norm and the idle steps are high (meaning the idle air control valve has to open a lot) than a fuel induction service would likely help.

Techron and other fuel additives are good, but the only clean injectors and the intake valves. They likely don't help the hard carbon on piston tops very much at all. Those additives certainly don't clean throttle valves, idle air controls and other vacuum lines at all.


2. Your coolant is good for 100K miles IF you never loose a drop of coolant and your system is completely full at all times. The likelyhood of this actually happening is slim to none.

A little history on coolant real quick. The old coolant used in vehicle untill the 90's (the green stuff) is chemically based, that coolant was good because if the level dropped, the coolant residue would stick to the metal, effectively protecting it from rusting (steel) or corroding (aluminum). The coolant in most modern cars (blue for Honda, red or pink for Toyota, orange for GM and so on) is organically based. Organic based coolant is good, it's all considered "long life". The problem with organic coolant is that if the coolant level drops, there is no residue sticking to the metal, the metal will begin to rust or corrode. Bad news for people who don't bother to check their coolant level.

That being said. 100K is probably too much to ask out of any coolant. GM tried this years ago and now they have a class action lawsuit against them from all of the consumers who had leaking intakes on their V-6 vehicles. Considering it is nearly impossible to keep any cooling system completely full for 100K miles, it's probably best that it be flushed at 50K.

[SpringfieldSkins]

I have alot of paint chips on my car and was thinking about getting it repainted cuz its not that great lookin on the hood. My current paint is pearl or 2 tone? Some are suggesting me to just use the regular paint which doesn't allow for a shadow and what not? Any suggestions

Quite honestly, I don't know much about body work and painting. That is a field which I would completely different than auto mechanics. Sorry I don't have an answer for you, hopefully someone around here should.

[Reic]

can you fix the air conditioner unit in my bedroom?

[SpringfieldSkins]

How do you clean a drive by wire throttle body? I am afraid to touch the butterfly valve with anything.

You should be able to turn the key to the on position and have somebody step on the gas pedal to open it up. Make sure it's somebody you trust because if they slip you could really end up hurting yourself. If in doubt, take it to somebody who is qualified to work on it.

[Redskins Diehard]

At what mileage should the timing belt of a 98 Infiniti I30 be changed?

[SpringfieldSkins]

Why do you try to sell extra services?

To make extra money of course.


But really, I've never sold somebody anything that their car didn't need. If their transmission fluid was jet black, I'd explain the repercussions of flushing or not flushing that nasty stuff out.

[HogNose]

Is it common practice at dealerships for service advisors to target cars coming in for state inspections for " unneccessary repairs" that are needed to pass inspection? I guess what I'm trying to say is do dealerships ever say, "You need that front strut replaced or it won't pass inspection". Joe Blow then panics because he doesn't want a rejection sticker and says.."Ok, go ahead and fix it". When the front struts are in fact perfectly fine and don't need to be replaced. It would seem to me that state inspections are the perfect time for dealerships to increase profits.

[SpringfieldSkins]

Should you engage the parking break on an automatic even on level ground? If so, should you do it while the car is in drive/reverse, or in park?

I've heard all different things on that subject.

I've seen many people who don't ever use their parking brake have parking brake problems.

Classic scenario: Car comes in for VA safety inspection. Same car fails inspection because the parking brake won't hold the vehicle (in VA, the parking brake must hold the vehicle while in drive at a stop). I call the customer and their response goes something like this, "What? My parking brake doesn't hold, but I don't even use it!".

The parking brake is cable operated, the cable goes from the lever (up front) to the rear wheels. The metal cable is shrouded in plastic or rubber. Over time of that cable not moving, rust builds up inside the insulation of the cable. The rust will build up so much that the cable will not move when you use the parking brake, effectively making the parking brake useless.


My suggestion, when you park your automatic car, engage the parking brake. You could only help prevent problems and further cost by doing this.