why is my mechanic telling me to replace my thermostat gasket and water pump? MIL Code says engine lean?

Question

He also says I need to replace my intake manifold gasket because there is a lack of upstream heated oxygen. what is heated oxygen?
Should I pay him the $500 bucks?

Answer 1

He's talking total Bullsh*t. "Heated oxygen"?? That's a new one. I just asked my Dad and two brothers and they started laughing their heads off! This ain't some weird rocket ship, it's a car. And anyway, rockets used super-cooled oxygen but never mind.

If your engine's running lean it's fundamentally a mixture problem. Meaning it's related to the air and fuel mix that your engine's getting. If it's 'lean' it means it's not getting enough fuel in proportion to the amount of air; if it's 'rich' it's getting the opposite. (Engines run richer at startup. That's what the choke's for. Needs richer fuel to get a good healthy bang in a cold motor with cold oil. Race car mechanics always prefer to run a slightly rich fuel mix rather than too lean. They need heaps of power, for one, and running lean can overheat things and burn holes in pistons in a worst-case scenario. That's just for info, BTW.)

If you're going to replace the thermostat gasket you put in a new thermostat at the same time anyway, and he should know that. Thermostats are pretty cheap and the labour involved is the same, so any decent mechanic will save you another lot of labour charges and throw in a new one. It can only help the car.

The water pump makes the coolant run around the system. It doesn't alter your fuel mix. You can replace it six times and your engine will still run lean.

Ditch this highly inventive but swindling mechanic who's taking you for an absolute bunny and go to a reputable, franchised auto repair place -- who have a lot to lose if they screw up. And tell your friends to stay away from Mr 'Heated Oxygen'!!

Answer 2

I am not sure what kind of car you have or anything, but possibly what he is trying to tell you is that the heated oxygen sensor is bad. This is not an uncommon problem, a heated oxygen sensor is designed to heat the oxygen sensor faster than the exhaust would normally do so that the emissions can be controlled by the computer faster. An oxygen sensor doesn't work until it gets up to approx 500 degrees.

As far as a lean condition, this can be caused by a vacuum leak. I have never seen a lean condition caused by a bad thermostat. Now the intake gasket may be the source of the vacuum leak but I would take it to a different tech and get another opinion. If this is a GM vehicle with a 3.1 or 3.4 engine, then they are notorious for having bad intake gaskets. If this is what you have and the intake is leaking, request that they replace it with a steel fel-pro intake set. Plastic, which everyone else makes, lasts about as long as the original. Go steel.

Answer 3

As Midas said, their is a heating element in the o2 sensor to get it to proper temperature faster. It should be Heater equipped oxygen sensor more than the technical name at times.

Only reason I would change a water pump is if it was leaking or the car was overheating basically.... ask him why he wants to change it... If not one of those two reasons run away.

Depending upon the intake manifold gasket, these gaskets are leaking far more common these days than say 5 years ago as most manufacturers are going with plastic or rubber o-rings that become brittle,crack and set the check engine light.

But probably the code he had was lack of Heated o2 sensor switching .. meaning the o2 sensor wasn't detecting or over detecting oxygen.. but usually when a car runs lean, the car tries to correct by riching up the motor and actually forces the numbers low..not high..weird yes...

But wise thing would be a second opinion somewhere's else first

Answer 4

A good piece of advice for you. Fire your mechanic! Now go find a new mechanic and make sure that he is actually a licensed mechanic whom has attained certification through an apprenticeship program. Sounds to me that whom ever you took your vehicle too in the first place is but a back yard mechanic and some one whom does not understand newer systems. It could be that your water pump isn't working as well. Check it this way. A water pump that does not work properly will leak fluid as will a thermostat gasket.But a worn out water pump has absolutely nothing to do with the fuel mixture. A worn out water pump will cause your vehicle to overheat and if not replaced immediately, your engine at best will blow a head gasket, at worst, much more major damage will occur and the engine will need full replacement as a result. I would not be listening to this person, I would be finding myself a more reputeable mechanic to check out my vehicle if I were you.

Answer 5

Thermostat???? Is water leaking around the thermostat gasket? If not, you do NOT need to replace it.

Heated Oxygen?????? Either he is playing with you and try to get a laugh or else he is trying to rip you off. The ONLY oxygen used in a car engine is the normal oxygen MIXED with AIR.

Water pump??? Is it leaking? Is your car running hot? If NO in both cases he is trying to rip you off.

Do NOT and I repeat, DO NOT give this character $500. He will laugh ALL the way to the bank. Not only get a second opinion but GET ANOTHER MECHANIC!!!! Good luck. Pops

Answer 6

If your car is losing coolant either at the thermostat, water pump or intake manifold then yes, it could set a lean code. (sounds very much like a typical GM problem) A hot running car runs lean.

Answer 7

Does your car overheat? If you need a new thermostat gasket and water pump your car should be overheating. The engine codes will come up clean becasue they only deal with emission controls- not you coolant system. If you are unsure go to another mechanic or do the repairs yourself. The heated oxygen is the emissions that travel through your car. If you have an intake manifold leak you could be breathing in carbon monoxide poisiong.

Answer 8

That's nonsense. For one thing, lack of oxygen would cause your engine to run rich, not lean. And, there is no such thing as upstream heated oxygen. Stay away from that phony.

Answer 9

If your check engine light is still on, take it to local Autozone and they will read your codes for free, give you a printout of what's wrong. Engine lean codes can be oxygen sensor or mass air sensor. Good luck.

Answer 10

No the mechanic is trying to rip you off if he is your mechanic maybe you need to find another.There is no such thing as heated oxygen in a motor.Maybe you Miss under stood.