1994 Infinity Q45 White Smoke Out Exhaust Sometime

Reader Question I own a 1994 Infinity Q45. 170,000miles. Doesn’t over heat. Everything works good. Every now-and-then when I push the car at about 65mph or greater for a long period of time, I notice a little bit of white smoke coming from exhaust.

Engine temp is good. Engine sounds fine, no unusual noises. I’ve tried to identify the problem, however the fact that it’s not constant(meaning it doesn’t do it on start up nor driving long distances at about 60mph, or when it does happen, it stops after I turn the engine off then
restart and the engine temp is good.) is confusing.

It also has a strong fuel/oil smell to it. Obviously I need to take it to a mechanic but I’m trying to identify it so I can see if I can fix it myself. Do you think you
can help me identify the problem?

Hi there,

I don’t really “know” this vehicle off the top of my head as well as most others Ford, Chevy, Honda etc. etc. etc. I just don’t see that many Infinities to begin with let alone the Q45, so I am not really up to date on any recalls or technical bulletins etc. etc. but I can suggest this to you.

What I would want to do is rule out the possibility of a head gasket or internal coolant leak though. A simple cooling system pressure test should be able to do this for you. The mechanic will hook up a hand operated air pump to the radiator and manually inflate the cooling system with air while looking for a leak. I would be concerned/concentrating on a low seep at this point.

I would put pressure on the system and allow it to hold this pressure for an hour or so as I kept an eye on the pressure gauge to see if there is a drop in pressure due to a leak in the system. It just takes a small drop of coolant inside a hot engine to produce white smoke….and white smoke is usually caused by coolant entering an area of the engine that it should not….like a head gasket.

170K miles is a lot of miles and I would NOT want to do a head gasket replacement on this vehicle at this mileage, just because you will not get your money back out of the repair when you do sell it, and you are most likely going to uncover a lot of additional repairs needed when doing this repair….so the costs can easily get way out of hand at this mileage interval.

You can also look under the engine oil filler cap to see if there is any white/chocolate milk looking stuff attached to the bottom of the cap. This can indicate coolant has entered the engine compartment.

Once you are certain that you have ruled out the possibility of coolant leaking into the engine, then I would start with some other tests like reading the onboard computer codes, testing the emissions coming out of the tailpipe with an emissions testing machine, checking the spark plugs for signs of engine oil leakage (or coolant leakage) that will show up on the tips of the spark plugs, checking the catalytic converter to make sure it is doing its job of scrubbing/cleaning the exhaust from the engine.

The rich smell you smell could be due to coolant leaking in the engine, a gas/air mixture problem with a faulty computer sensor (like an oxygen sensor), worn out spark plugs or a catalytic converter that has stopped working……which would not surprise me at this mileage either.

But again, my personal main concern would be to make sure this is not the first signs of an internal coolant leak…..I would sell this car and move on to something else if coolant was leaking internally.

Just in case, I have had great success with this over the counter coolant stop leak (but only use this if you are certain coolant is leaking internally)

Internal Engine Coolant Leak

Keep me posted as to what you find out will ya?

Blessings,

Austin Davis