White smoke from tailpipes

[Falcon_LS]

I took my Grand Marquis to the dealership to diagnose occasional white smoke from the tailpipes under the following conditions:

- WOT
- Transmission kicks down to first
- Vehicle speed is over 60 km/h (38 MPH)

I’m not sure if it happens during downshifts from third to second or forth to third, I haven’t experimented. But the smoke only appears for the first few seconds, immediately after kick down, and leaves a large cloud behind the vehicle. It does not happen every single time, but it is embarrassing when it happens.

There are no traces of oily residue in either tailpipe now that the oil separator is in place and the engine does not suffer any loss in performance. Operation is super smooth, and there’s barely any drop in oil level with 10,000 km/6,250 mile drain intervals. No makeup oil is added during the interval, and there is only a very slight drop, I’d say about 200 ml or so tops. But nothing like half a quart or more.

I was really just after a compression test with IDS for peace of mind, and through my contacts got to deal with a quality controller and technician instead of a service writer. The car is booked in for Sunday, and I emailed my concern to the QC and tech for them to print on the day and refer to (comments in italics are for BITOG):

Quote:
Vehicle: 2001 Mercury Grand Marquis

Mileage: ~255,000 km (159,375 miles)

Maintenance: Rigorously maintained to exact factory service manual requirements, including use of full synthetic lubricants and genuine Ford/Motorcraft parts. Driven gingerly with occasional Wide Open Throttle (WOT) runs on closed roads. The engine oil (Liqui-Moly Synthoil Longtime 0W-30) level remains full throughout its service life (10,000 kilometres), and a Steeda oil separator has been installed in the PCV line to help keep the intake clean.

Engine idle and operation is super smooth with no hesitation whatsoever, although occasional pinging does occur.

Fuel type: 91 RON (87 AKI) unleaded (100 ml TC-W3/100 ml MMO added)

Problems:

• Slight coolant leak from intake manifold gasket located on the driver's side rear of the engine, near firewall
• Slightly worn pitman arm
• Transmission EPC solenoid requires replacement

Complaint: Occasional white smoke appears to be coming out of tailpipes under the following conditions:

- WOT
- Transmission kicks down to first
- Vehicle speed is over 60 km/h (38 MPH)

Smoke only appears immediately after kick down, and leaves a large cloud of white smoke behind the vehicle. It does not happen every single time.

Request: Compression test

Having said that, the tech replied to my email with the following:

Quote:
According to the document sent, and after reading it, my understanding is that there is coolant that is leaking, which needs to be fixed. Also the engine compressions have to be checked and even if the compression is ok there is BASE ENGINE concern, for the white cloud of smoke that Appears sometimes, possibly engine oil leaking past the Valve seals. Engine Overhaul required.


If the engine does not consume oil outside of what has been specified by Ford as “normal”, performs as expected and operates smoothly and quietly, why would an engine require an overhaul?

And what is a “base engine concern”, the bottom end? This has made me nervous, and I’m now looking forward to the compression test more than ever.

 

[Hokiefyd]

His definition of "engine overhaul" might be different from ours. It looks like the engine will need, at a minimum, a valve job in the heads to correct the seals. The Modulars will typically put out blue smoke, though, when the valve seals our bad. Our '92 Crown Vic did, like a chimney. I though they fixed this problem in the mid-90s?

Aside from the intake manifold gasket leak and the valve seal leaks, I don't see any indications that further work would be required.

 

[demarpaint]

White smoke usually means either condensation, which after the engine is warmed up is no longer an issue. Or coolant leaking inside the engine, bad head gasket. Try pressure testing the cooling system to R/U a head gasket. Then do a compression test, if the pressure testing does in fact R/U a bad head gasket. You mentioned slight coolant leak, my bet is a head gasket, you could be leaking inside and outside the engine. There is a slight chance it is valve seals too, but oil smoke is not "white". JMO

 

[Falcon_LS]

The valve seal issue was corrected in 1996.

When I bought the car, it actually had problems with the valve seals, but I now use Liqui-Moly Motor Oil Saver at every oil change, which is an ester-based additive that rejuvenates seals.

Ever since, there has been no smoke after starts, at idle or as you drive off. That's why I was wondering how the valve seals would be the culprit, especially considering the amount of oil that is used.

 

[Falcon_LS]

Originally Posted By: demarpaint
White smoke usually means either condensation, which after the engine is warmed up is no longer an issue. Or coolant leaking inside the engine, bad head gasket. Try pressure testing the cooling system to R/U a head gasket. Then do a compression test, if the pressure testing does in fact R/U a bad head gasket. You mentioned slight coolant leak, my bet is a head gasket, you could be leaking inside and outside the engine. JMO


Would a leaky head gasket not cause the oil to get all milky? Because there are no traces of coolant in the oil or oil in the coolant.

The coolant leak is actually visible underneath the vehicle when it is parked, but it very well could be possible that coolant is leaking through the intake manifold gasket into the combusion chamber.

 

[bullwinkle]

I'd get the IM gasket replaced and keep on driving and see what happens!

 

[mpvue]

it's a coolant leak. coolant is white smoke, oil is blue smoke. not all coolant leaks are into the oil, so you can have white smoke but no milky oil.
least case, bad intake manifold or other gasket.
worst case, cracked water jacket in one of the cylinder heads.

 

[Trav]

On top of everything mentioned you may have an injector malfunctioning at WOT. Light grey/white smoke is a common sign of a injector malfunction, if its bad enough at idle the engine can miss and the smoke can be copious but improves with high RPM.

When an engine with normal heated O2 sensors like yours is in WOT mode the ECM will no longer attempt to maintain stoichiometric,
instead it will allow the injectors to run wide open in open loop creating a condition similar to static flow at the injector. You may have one flowing substantially more than the others under that condition causing this white smoke.
Wide band air-fuel ratio meters will maintain stoichiometric throughout the RPM range including WOT.

A injection testing machine can identify or rule this out quickly. The offending injector(s) if there is one must be replaced as it is electrically compromised.
I cant say with any certainty this is the cause, it's just another possibility.

 

[Falcon_LS]

Originally Posted By: bullwinkle
I'd get the IM gasket replaced and keep on driving and see what happens!


Probably going down that route actually.

Originally Posted By: mpvue
it's a coolant leak. coolant is white smoke, oil is blue smoke. not all coolant leaks are into the oil, so you can have white smoke but no milky oil.
least case, bad intake manifold or other gasket.
worst case, cracked water jacket in one of the cylinder heads.


Biggest problem here is nobody replaces coolant. I replaced 9 year old coolant on this car that had turned to brown sludge when I bought it last year. Inevitibly, I took the risk of a coolant leak later on, which is what I'm facing now.

Originally Posted By: Trav
On top of everything mentioned you may have an injector malfunctioning at WOT. Light grey/white smoke is a common sign of a injector malfunction, if its bad enough at idle the engine can miss and the smoke can be copious but improves with high RPM.

When an engine with normal heated O2 sensors like yours is in WOT mode the ECM will no longer attempt to maintain stoichiometric,
instead it will allow the injectors to run wide open in open loop creating a condition similar to static flow at the injector. You may have one flowing substantially more than the others under that condition causing this white smoke.
Wide band air-fuel ratio meters will maintain stoichiometric throughout the RPM range including WOT.

A injection testing machine can identify or rule this out quickly. The offending injector(s) if there is one must be replaced as it is electrically compromised.
I cant say with any certainty this is the cause, it's just another possibility.


Thanks for the heads up!

Quick question though; Panther vehicles featuring export specifications did not come with oxygen sensors or catalyic converters in 2001, so would that affect the injectors' wide open mode in any way?

 

[Trav]

WOW 2001, i remember GM exports in the 80's being done like that.
The car still uses an ECM so i am thinking the O2 inputs were just eliminated in the ECM as GM did relying instead on throttle position, rpm, coolant temp, MAF or MAP to regulate injector flow and timing in closed loop operation.
The scenario during WOT would be the same.

You can check the ohms of the injectors terminals at the connector (unplugged) with a cheap VOM, look for one with ohms lower than the others.
This is not 100% as you cant test the mH with the injector firing but it is very common that injectors with higher flow rates than the others during WOT show a static reduction in ohms.

Look for a significant difference of say more than 2 ohms, if 7 are 13.8-14.5 for example one with 12 would certainly be suspect.
Your injectors i believe are Bosch sequential units (probably yellow tops)so they will have a value in the 14+- ohm range.

Some peak and hold units are only in the 2-3 ohm range, this is just info for someone testing ohm's their injectors.

 

[demarpaint]

Originally Posted By: Falcon_LS
Originally Posted By: demarpaint
White smoke usually means either condensation, which after the engine is warmed up is no longer an issue. Or coolant leaking inside the engine, bad head gasket. Try pressure testing the cooling system to R/U a head gasket. Then do a compression test, if the pressure testing does in fact R/U a bad head gasket. You mentioned slight coolant leak, my bet is a head gasket, you could be leaking inside and outside the engine. JMO


Would a leaky head gasket not cause the oil to get all milky? Because there are no traces of coolant in the oil or oil in the coolant.


Not all the time, it depends on how bad it is. The fact that you have a coolant leak is strike one. You could pull an oil sample and send it off for testing. A pressure tester is going to force coolant out from all leaking areas and will certainly push coolant into the oil if that's the problem. Since you have an external coolant leak the tech doing the pressure testing might not be able to detect coolant going into the oil, the UOA will if the tech can't.

 

[mechtech2]

Note any coolant loss.

 

[Falcon_LS]

An update on the situation. Through a contact, I got the car on a dynometer. At WOT, there is coolant spraying down the valve cover and onto the hot exhaust manifold, causing the white smoke.

As the vehicle is in motion otherwise, it makes it look like the white smoke is coming from the exhaust, when in fact it's coming from under the hood. There is also a barely visible crack on the intake manifold crossover. Only reason you can see it is because of the white residue left on it.

During the first two runs, you had brownish smoke coming out, but it went away after that. No smoke whatsoever out the exhaust afterwards, and it is clean.

For the time being, I'm going to avoid any WOT runs until I get all the parts together and allocate a time to replace it.

 

[mechtech2]

What part is leaking onto the manifold?

 

[PandaBear]

Personal experience is if you can notice the white smoke in warm weather, it is most likely head gasket. What about idling after you drive for a while? If you see white smoke after the car is warmed up and in idle, you might have leaky head gasket.

 

[The_Eric]

Didn't you replace that intake? I thought I remembered you asking about them once?? The originals were plastic in the crossover area and like to blow out. The (new) O.E. and after market replacements are aluminum. Either way, I've seen the results of the coolant crossover going and it's a bad deal.

 

[Falcon_LS]

Originally Posted By: mechtech2
What part is leaking onto the manifold?


The manifold gasket was already leaking, but there's also a crack on the side of the intake manifold. It's the intake manifold leaking onto the exhaust manifold.

Originally Posted By: PandaBear
Personal experience is if you can notice the white smoke in warm weather, it is most likely head gasket. What about idling after you drive for a while? If you see white smoke after the car is warmed up and in idle, you might have leaky head gasket.


Thankfully, the exhaust does not smoke.

Only time you see it is when coolant sprays onto the exhaust.

Originally Posted By: The_Eric
Didn't you replace that intake? I thought I remembered you asking about them once?? The originals were plastic in the crossover area and like to blow out. The (new) O.E. and after market replacements are aluminum. Either way, I've seen the results of the coolant crossover going and it's a bad deal.


The gasket was replaced in January, but the manifold itself wasn't. Technically I should have replaced it, but my mechanic kept telling me there was nothing wrong with it and I gave in.