Ask a mechanic thread... Q & A with an ACTUAL mechanic!

[GreatWhiteEbola]

Originally Posted by TOTO Flames

Valve impression on the pistons is a good indication. In my experience oil on spark plugs is a leaking valve cover. The best test is a compression test. If you have low or 0 compression, chances are you bent valves. Obviously to do this you have to replace the timing belt. Also the sound of the vehicle when you turn it over is a good indication of bent valves. If it sounds like a spinning wheel and not an engine that turns over, chances are you damaged the valves.

Having said that, most interference engines once the belt snaps the cylinder head needs to be removed for further evaluation and from experience its never good.

As I suspected, I can't take a short cut.

I have already replaced the timing belt, and then when I went to do a compression test I witnessed the oil on the plugs, so I held off the compression test. I think I'll try the compression test this weekend and see what my findings are. I have another head, which is fortunate, it's so much bloody work though, lol...

[Flacker]

Originally Posted by WCan_Kid

I've put this out to a number of people and it remains a pure mystery.
1998 Porsche Boxster, runs like a dream most of the time, but when outside temps get into the 30's it will randomly stall.
No warning, no codes thrown, just all of a sudden the engine stalls. Never happens on cooler days and it doesn't matter if it's idling in a parking, driving city speeds (50-60km/h) or highway speeds (100km/h +).
I do get a whiff of gas, like it's flooded, just after it happens and if I'm stopped it acts like an old carburated engine would when flooded. On the highway I can just push the clutch in and then release to jump start it again, will run fine after that for a random amount of time (1/2km to 1 or 2 km's before stalling out again).
Have had it checked out and the tank lines re-routed at an independant Porsche shop to no avail, along with other shops/mechanics including my usual guy who typically figures out anything I throw at him.

This sounds like vapor lock. The high temperatures being the trigger. Sounds like the fuel lines have been re-routed, they likely suspected the same. Is there somewhere the fuel lines are getting close to hot stuff (exhaust, cat, manifold, etc)?

[TOTO Flames]

Originally Posted by WCan_Kid

I've put this out to a number of people and it remains a pure mystery.
1998 Porsche Boxster, runs like a dream most of the time, but when outside temps get into the 30's it will randomly stall.
No warning, no codes thrown, just all of a sudden the engine stalls. Never happens on cooler days and it doesn't matter if it's idling in a parking, driving city speeds (50-60km/h) or highway speeds (100km/h +).
I do get a whiff of gas, like it's flooded, just after it happens and if I'm stopped it acts like an old carburated engine would when flooded. On the highway I can just push the clutch in and then release to jump start it again, will run fine after that for a random amount of time (1/2km to 1 or 2 km's before stalling out again).
Have had it checked out and the tank lines re-routed at an independant Porsche shop to no avail, along with other shops/mechanics including my usual guy who typically figures out anything I throw at him.

Have you tried a fuel pump or like the Mr.Bumface(great handle btw) said a mass air flow sensor?

[bigtmac19]

Originally Posted by TOTO Flames

That's smart on your part, we have proper parts in stock. Something as small as bulbs can cost you more in the long run due to incorrect wattage on bulbs leading mechanics astray when diagnosing.

That being said where would you start diagnosing electrical issues?

[WCan_Kid]

Originally Posted by TOTO Flames

Have you tried a fuel pump or like the Mr.Bumface(great handle btw) said a mass air flow sensor?

Swapped out the fuel pump, not MAF sensor though. Assumed one of the mechanics that's looked at it would have caught that, but it's never been mentioned. Thanks all, remind me to never buy a car with a hidden engine again.

[Fuzz]

It does sound a lot like vapour lock though. Does it always happen buying gas from one station? or do you use variety? Different companies formulate summer gas differently.

[TOTO Flames]

[QUOTE=bigtmac19;5932941]That being said where would you start diagnosing electrical issues?[/QUOTE

Look for the obvious, damaged wiring causing shorts or opens. Usually found in the areas where they are stressed the most like a door jam.

[calgaryblood]

What's the best oil in your opinion for high mileage vehicles?

[btimbit]

What would cause a rocker arm to come off? Pulled my valve cover the other day to do a timing chain and noticed one was just laying in the corner of the cover. Rocker arm itself was in decent enough condition, no worse than the rest of them. Wasn't seized or anything.

I guess sloppy timing chain wasn't the only reason she ran rough

[InglewoodFan]

Thanks TOTO for offering your expertise.

Was wondering about brakes. I had my Audi in for regular service, and as part of the inspection they give the remaining life left on the brake pads. The paperwork they gave me indicated 5-6 mm in the back and 6-7 mm in the front. All good. I was also getting a warning light for a general brake issue that the dealership attributed to slightly low brake fluid. Level looked good to me but they topped it up and the warning light went away.

Three weeks later I'm getting bad shuddering and noise when braking, take the car back in and the rear pads are completely gone. Can you think of anything that would run 5 mm of pad wear off in less than 500 km? Could it have anything to do with the fluid level change? (I don't think so as it is an open system). Also, in your experience do you often see rears wear out long before fronts? I've always had the fronts go sooner due to them taking more of the braking load.

[DownhillGoat]

Originally Posted by Bill Bumface

^I'll let the real mechanic chime in, but have you ruled out a bad MAF?

If it's anything like the 996 you get a combination of telltale codes on MAF failures.

I'd try cleaning it (only a temporary fix), which would at least rule it in/out before replacing it.

[ricosuave]

Thanks for taking the time to do the things we never had.

[IliketoPuck]

Question for the mechanic:

I dropped my 2013 Santa Fe off for oil change / brake maintenance this morning.

Got the predictable call about 5 minutes ago that "our records show"

1. you should get your transmission flushed. (for only $270 bucks).
2. you should get your coolant flushed. (for only $200 bucks).
3. you should get an emission service completed to reduce carbon build up. (for only $200 bucks).

I'm no mechanic, but I sure as hell don't like to see my service bill go from oil change and brakes to >$1000 bucks.

Thoughts on the validity of the suggested services?

[puffnstuff]

Originally Posted by InglewoodFan

Thanks TOTO for offering your expertise.

Was wondering about brakes. I had my Audi in for regular service, and as part of the inspection they give the remaining life left on the brake pads. The paperwork they gave me indicated 5-6 mm in the back and 6-7 mm in the front. All good. I was also getting a warning light for a general brake issue that the dealership attributed to slightly low brake fluid. Level looked good to me but they topped it up and the warning light went away.

Three weeks later I'm getting bad shuddering and noise when braking, take the car back in and the rear pads are completely gone. Can you think of anything that would run 5 mm of pad wear off in less than 500 km? Could it have anything to do with the fluid level change? (I don't think so as it is an open system). Also, in your experience do you often see rears wear out long before fronts? I've always had the fronts go sooner due to them taking more of the braking load.

Rears can and will wear out faster than the fronts. The pads are smaller, surface area wise. Ive done rears before fronts a number of times. As to the measurement given before, I may be making an assumption here, but sometimes they only look at the outboard pad and see there is still material there. But the inboard one is actually more worn. The low fluid level is actually a pretty good indicator that the pads are worn. As the fluid is a closed system, when the level drops in the reservoir it means its filling space somewhere, basically because the pads have worn and more fluid is in the caliper behind the piston.

[YYC in LAX]

How much should I pay for a remote starter install for my 2006 Tundra?

[Weitz]

Question for the Mechanic:

I've got a ford with an 'EcoBoost' engine. I have had a friend tell me that you shouldn't take the RPM's up over 2500 until the engine is sufficiently warm. I generally don't if I am driving. But the GF is a little crazier. I imagine there is soem sort of truth to this, but without a temp gauge for the engine whats a good "warm up time"?

Thanks.

[Calgary14]

Originally Posted by IliketoPuck

Question for the mechanic:

I dropped my 2013 Santa Fe off for oil change / brake maintenance this morning.

Got the predictable call about 5 minutes ago that "our records show"

1. you should get your transmission flushed. (for only $270 bucks).
2. you should get your coolant flushed. (for only $200 bucks).
3. you should get an emission service completed to reduce carbon build up. (for only $200 bucks).

I'm no mechanic, but I sure as hell don't like to see my service bill go from oil change and brakes to >$1000 bucks.

Thoughts on the validity of the suggested services?

I'm not a mechanic so I can't speak to the validity of those services but I used to get those calls all the time when I took my vehicle in to the dealer. The last straw was when they called to recommend numerous services that added up to over $2k (the car is only worth around $6k).

I switched to a reputable, affordable (and honest) mechanic who charges less than half what a dealer would charge, and I started doing some of the basic stuff (oil changes) myself.

If you're skeptical about their recommendations I would get a second opinion from a third party that doesn't do any work themselves like inspectacar and see what they say about what the vehicle actually needs.

And I would also check the schedule of maintenance, not sure about your vehicle or the current KMs but my vehicle calls for a transmission fluid change at 100,000km

[Fuzz]

Originally Posted by Weitz

Question for the Mechanic:

I've got a ford with an 'EcoBoost' engine. I have had a friend tell me that you shouldn't take the RPM's up over 2500 until the engine is sufficiently warm. I generally don't if I am driving. But the GF is a little crazier. I imagine there is soem sort of truth to this, but without a temp gauge for the engine whats a good "warm up time"?

Thanks.

Depends on the vehicle. When warm air comes out of the vents is a good indication the engine is warm.

[Language]

Thanks for this thread.

Regarding timing belts, should one get it replaced when it is recommended by the vehicle manufacturer?

Say you decide not to change it and the timing belt breaks. Would the outlay to fix it be equal to what it would have cost to fix it as preventative maintenance? If so, I don't see the point to replace it until it has broken, unless the cost to replace it at that point (after it's broken) is exponentially greater.

[zamler]

Originally Posted by IliketoPuck

1. you should get your transmission flushed. (for only $270 bucks).

I did a quick check and couldn't find a maintenance schedule for the transmission, maybe I missed it. But the transmission is an often neglected component so getting the fluid changed is cheap insurance, assuming the dealer will do the job properly. The price you are quoted does seem a bit high.

2. you should get your coolant flushed. (for only $200 bucks).
3. you should get an emission service completed to reduce carbon build up. (for only $200 bucks).

For the coolant follow the maintenance schedule, "emission service" skip that and buy a fuel additive like Lucas Upper Cylinder Lubricant

I'm no mechanic, but I sure as hell don't like to see my service bill go from oil change and brakes to >$1000 bucks.

Typical and expected.

Originally Posted by Language

Say you decide not to change it and the timing belt breaks. Would the outlay to fix it be equal to what it would have cost to fix it as preventative maintenance? If so, I don't see the point to replace it until it has broken, unless the cost to replace it at that point (after it's broken) is exponentially greater.

Depends on the engine, almost all Toyota engines with a timing belt are non-interference so when the belt breaks the engine simply stops no damage. Honda is almost always an interference engine meaning the pistons will collide with the valves and bend them, $$$$$. But a broken timing belt is a safety issue you could be trying to cross traffic and lose power. Pay now or potentially pay much more later.