The "Ask a Mechanic" Thread

[Mickalino]

Hey guys

What exactly does it mean, if your oil pressure gauge indicates low pressure, and it's in the Red ?

I've googled and found it could be from a number of sources, but is there anything an amateur like myself can check, to rule out anything ?

Thanks

Edited January 18, 2010 by Mickalino

[twa]

Hey guys

What exactly does it mean, if your oil pressure gauge indicates low pressure, and it's in the Red ?

I've googled and found it could be from a number of sources, but is there anything an amateur like myself can check, to rule out anything ?

Thanks

Means you are gonna fry the motor unless it is a bad sensor or very thin oil

Check the oil level first.

could be a bad sensor or bad oil pump/plugged filter

Does it have a tapping or clattering noise?

Does the light only come on at a idle?

added

I assume yours has a gauge not a light?..if so does the pressure only drop at idle?

Edited January 18, 2010 by twa

[Mickalino]

Means you are gonna fry the motor unless it is a bad sensor or very thin oil

Check the oil level first.

could be a bad sensor or bad oil pump/plugged filter

Does it have a tapping or clattering noise?

Does the light only come on at a idle?

added

I assume yours has a gauge not a light?..if so does the pressure only drop at idle?

I checked the oil level, that's fine.

There's no noise coming from the engine.

It is a gauge and not a light. And it remains low constantly, whether idling or driving.

I just bought it as a used vehicle from an individual. And everything looked and drove fine. I just didn't notice the gauge level until after I bought it and drove it home.

I called him back, and he said something about the "switch from the sending unit" is bad.

But I don't know if he's being honest, or possibly covering up the fact that it needs an engine overhaul, which I'm afraid of, after researching options on the internet.

[twa]

A plugged sending unit can very well do that,don't cost much

Generally if the pressure is truly low the lifters start clattering

W/o hooking up a manual gague it is hard to say...you can buy those fairly cheap

Edited January 18, 2010 by twa

[Mickalino]

Is that something that a place like Auto Zone or Advance Parts will do for free, with one of those small diagnostic boxes they use ?

[RememberOsaka]

They have common transmission, rear differential, electrical and air conditioning problems as seen in most Chrysler models. Asking how well a car will last is a tough question because people will care for them differently. That said, even with the best care, Jeep Cherokees will run into a litany of problems.

What's funny is that the Jeep GC gets terrible reliability reviews yet I owned a 1996 and put 174k on it and only had to replace the trans cooling lines at 100k and the power steering pump at 125k. Sold the car for $4500 in 2005.

I bought a 2005 Jeep GC and have 92K on it and have 20% brake life left, never paid for any repair other than new tires.

[DarrellsMyHero28]

I failed the state inspection because of a broken motor mount (one the side of the engine).

After replacing it my mechanic (Merv's in Springfield, SS I'm sure you're familiar with them) found that my rear motor mount was cracked.

They said that it wouldn't be a big deal because that motor mount only really came under stress when the car was in reverse so unless I put it in reverse for a long period of time it wouldn't be an issue.

Thoughts? I don't like the idea of having any problems with the mechanism that holds in my engine.

Edited January 18, 2010 by DarrellsMyHero28

[Leonard Washington]

Anyone have experience with Subarus? Particularly the turbo Legacies?

[DCsportsfan53]

Anyone have experience with Subarus? Particularly the turbo Legacies?

It needs a head gasket

Not useful, I know, just couldn't resist, I don't have any experience with them

[twa]

I failed the state inspection because of a broken motor mount (one the side of the engine).

After replacing it my mechanic (Merv's in Springfield, SS I'm sure you're familiar with them) found that my rear motor mount was cracked.

They said that it wouldn't be a big deal because that motor mount only really came under stress when the car was in reverse so unless I put it in reverse for a long period of time it wouldn't be an issue.

Thoughts? I don't like the idea of having any problems with the mechanism that holds in my engine.

It is not really a safety hazard but it will put extra strain on the others causing them to fail faster.

They usually are designed so even if the rubber fails it will not go anywhere,just have slack.

The usual recommended route is to replace them all at the same time

MICK....No idea if the scanner would pick it up since it will only read what the sending unit sends

They might have a mechanical gauge they loan ,but I doubt it.

[twa]

It needs a head gasket [/size]

From my experience the owners need some head...or something:silly:

[Mickalino]

It needs a head gasket

My last car blew a head gasket.

It's a shame.

My car gets more blown head, than I do

[Springfield]

I guess it doesn't have a "normal" fuel pump mechanism (according to my dad) and the mechanic called me today and said the pump injector thingy has to be replaced along with the filter...to the tune of approximately 975. AHHHH!!! Does that sound right?

Sorry it took me so long to get around to it.

You're in Southern California right? $975 sounds just about right for my area so I'd assume the same for yours.

The fuel pumps fail quite often on those cars. We replaced one a week or two ago, it was expensive as hell. What makes it so expensive is that the fuel pump comes as a complete module. This module contains the level sensor and all the other electronics that have to do with the fuel pump inside the tank. Also, as I remember, the tank has to be dropped to replace the fuel pump.

[Springfield]

My girlfriend has a 2000 Toyota Solara. She was told she has a cracked radiator. It is currently not leaking fluid.

To fix it would cost $350. (she does not remember if this was to fix the crack or replace the whole thing) As fas as she knows, the radiator has never been replaced.

Questions:

Is the car safe to drive or should it be driven straight to a mechanic?

Does is make sense to repair the radiator or replace it?

What is a reasonable charge for that?

A co-worker is a "car guy" and said he'd replace the radiator at cost. Is that something that could be done in my work parking lot or is it better to let a pro do it?

Thanks in advance.

As twa said. It's safe to drive until the radiator starts leaking. The main concern is the loss of coolant and thus the overheating that would occur when the coolant gets low enough.

Personally, I would replace the radiator. As I said pages and pages ago in this thread, I don't believe in "stop leak", "bars leak" or any other sort of "repair" to a cooling system. I think you can save yourself a lot of trouble in the long run by fixing it right the first time. Some poster did seem to think that an egg would do a great job of sealing up a leak in the cooling system though.

Reasonable charges normally depend on the area. Rural areas are less expensive than urban areas and more affluent areas are the most expensive. $350 is more than reasonable in my area.

It's not hard to replace the radiator on that car if I remember correctly. If you trust your friend, I'd give him a shot. It's not something that requires a lift, so it certainly could be done in a parking lot.

[Springfield]

Hey guys

What exactly does it mean, if your oil pressure gauge indicates low pressure, and it's in the Red ?

I've googled and found it could be from a number of sources, but is there anything an amateur like myself can check, to rule out anything ?

Thanks

I'll say with fair certainty that your oil pressure gauge is faulty. The good news is that they aren't that hard to replace either.

The oil pressure gauge going to the red means exactly that, it's saying you have low oil pressure. The thing is, if your pressure gauge is low and you're driving around on it, you'd be hearing all sorts of tapping from your engine. Before long, the motor would lock up.

Since that hasn't happened yet, it's fair to say that your oil pressure sensor is not reading out correctly.

Also, it's a very common problem on those cars. I'd save the cost of an oil pressure test and just have somebody replace the sensor. Shouldn't cost a whole lot of money.

[Springfield]

Is that something that a place like Auto Zone or Advance Parts will do for free, with one of those small diagnostic boxes they use ?

No, you're going to have to pay a mechanic to replace it. The car will likely have to be put up in the air... it makes it much easier.

[Springfield]

What's funny is that the Jeep GC gets terrible reliability reviews yet I owned a 1996 and put 174k on it and only had to replace the trans cooling lines at 100k and the power steering pump at 125k. Sold the car for $4500 in 2005.

I bought a 2005 Jeep GC and have 92K on it and have 20% brake life left, never paid for any repair other than new tires.

That's good. Glad you've had great reliability out of both. Hopefully you'll have continued success.

I'm not saying that every Grand Cherokee ever made will fail. I can say with confidence though that there are probably more problems I see with them regularly than I can name on one hand.

They do have terrible reliability reviews for a reason though.

[Springfield]

I failed the state inspection because of a broken motor mount (one the side of the engine).

After replacing it my mechanic (Merv's in Springfield, SS I'm sure you're familiar with them) found that my rear motor mount was cracked.

They said that it wouldn't be a big deal because that motor mount only really came under stress when the car was in reverse so unless I put it in reverse for a long period of time it wouldn't be an issue.

Thoughts? I don't like the idea of having any problems with the mechanism that holds in my engine.

Merv's are good people. I can't say anything bad about them.

It is likely that your broken motor mount didn't help the rear motor mount though. I doubt it is a big deal right now and they probably wanted to let you know so that you wouldn't be back in a year with a broken motor mount (the rear one now) complaining that they just fixed one.

Either way, it shouldn't be a big deal... yet.

Oh and yeah, your engine won't fall out of your car... even if it's broken. There are at least three, if not more, mounts that support everything. Your engine wouldn't fall out even if they were all broken.

[Springfield]

Anyone have experience with Subarus? Particularly the turbo Legacies?

Overall, they are fairly reliable. The one thing I see wrong with a number of Subaru's is their front crank seal. The crank seals tend to leak quite often.

The crank seal is what seals the crankshaft from the outside world (so to speak). In order to replace it, you have to remove the timing belt. Quite a bit of labor to replace it.

I've also seen an increasing number of catalytic converter failures on most Subaru models. Usually ones that have more than 100K on the odometer though. They are hugely expensive to replace because you have to get the OEM part (aftermarket converters on Japanese and European vehicles are terrible). It isn't a statistically high number of failures based on the numbers of Subarus that we see, but it's worth noting.

[DarrellsMyHero28]

Merv's are good people. I can't say anything bad about them.

It is likely that your broken motor mount didn't help the rear motor mount though. I doubt it is a big deal right now and they probably wanted to let you know so that you wouldn't be back in a year with a broken motor mount (the rear one now) complaining that they just fixed one.

Either way, it shouldn't be a big deal... yet.

Oh and yeah, your engine won't fall out of your car... even if it's broken. There are at least three, if not more, mounts that support everything. Your engine wouldn't fall out even if they were all broken.

Thanks SS, you're a good man.

[Mickalino]

I'll say with fair certainty that your oil pressure gauge is faulty. The good news is that they aren't that hard to replace either.

The oil pressure gauge going to the red means exactly that, it's saying you have low oil pressure. The thing is, if your pressure gauge is low and you're driving around on it, you'd be hearing all sorts of tapping from your engine. Before long, the motor would lock up.

Since that hasn't happened yet, it's fair to say that your oil pressure sensor is not reading out correctly.

Also, it's a very common problem on those cars. I'd save the cost of an oil pressure test and just have somebody replace the sensor. Shouldn't cost a whole lot of money.

If it's just the gauge that isn't working, then what's the risk, if I try to save money on the mechanical shop bill by letting it slide ?

Of course, if I don't fix it, I wouldn't have a gauge to tell me when my oil pressure is actually low. But can't I just wait until I hear the pinging before I repair the parts that are causing the oil pressure to go down. Or will it be too late when I hear that sound, and already had damage done ?

[Springfield]

If it's just the gauge that isn't working, then what's the risk, if I try to save money on the mechanical shop bill by letting it slide ?

Of course, if I don't fix it, I wouldn't have a gauge to tell me when my oil pressure is actually low. But can't I just wait until I hear the pinging before I repair the parts that are causing the oil pressure to go down. Or will it be too late when I hear that sound, and already had damage done ?

That's your answer. If you hear knocking and pinging because of low oil pressure, it's already too late. At that point, you'll probably need major engine repairs.

Now... the chances of that actually happening aren't too high. For a repair that costs $100-$150 in my (high priced) area, I'd say it's worth it though. Just to have the piece of mind.

[BayouBrave86]

Better brand, Chevy or Jeep? I'm FINALLY looking to get a newer model Jeep or Chevy. I'm looking at the 05-07 Grand Cherokee's and Trailblazers. I'm wondering which one might be more reliable. Any advice would be much appreciated. I have a 96 Grand Cherokee right now and the thing has been an absolute warrior for me. It's at 165,000 right now and it could probably last for a couple more years.

Edited January 20, 2010 by BayouBrave86

[twa]

Chevy imo.

[Veretax]

Could spark plugs nearing their end of life expetancy cause the car to shimmy some at low speeds when the car hasn't been running for too long?