White Smoke Billowing From Exhaust After Repairs

I just had my 2011 Nissan Xterra repaired at the local Nissan dealership. They replaced the catalytic converter, two 02 sensors, a coil, and all new spark plugs. The day after I brought it home from getting these repairs, white smoke billows from the exhaust pipe, upon starting the vehicle. This white smoke problem never occur until the day after they did these repairs. There is a bunch of white smoke coming from the exhaust upon starting the vehicle-- it lasts for about 5 minutes and then dissipates when driving. After the car sits for a few hours, the white smoke problem occurs again when starting the vehicle. Can someone please provide some insight into what can be causing this white smoke problem to start occurring, after the dealership did these repairs?

I suspect that you brought the vehicle to the shop for a check engine light/misfire problem and the real cause of the misfire was coolant leaking into one of the cylinders. Now the problem is much worse, there is a lot of coolant leaking into one or more cylinders.


Why did they want to replace cat and coils and plugs?
Check engine light? Poor performance?
Did motor smoke when repair was done at dealer?

@Nevada_545 is correct as usual. The shop misdiagnosed a head gasket problem and threw a bunch of parts at it. Now you’re out the cost of the repair and you still have an expensive problem to solve.

Yes, the check engine light was on, then after about two weeks of it being on, the light started flashing, and there were obvious misfires, which prompted me to immediately bring the car to the service department. They told me the catalytic converter needed to be replaced, as well as a coil, and all of the spark plugs. They called me back and also told me the two 02 sensors were melted from the catalytic converter getting too hot, so they replaced those as well. The white smoke didn’t occur when I picked the car up from the dealership, but it started the very next day, after I started it for the first time at home. There are no more misfires, and the check engine light isn’t on, however when idling, it can feel a bit “clunky” ever so often. If there is coolant leaking into one of the cylinders, is this something they should be fixing free of charge? Its just awful ironic that there was no smoke coming from the exhaust, until after their mechanics touched the vehicle. I already put over $3,100 to get all of this stuff repaired…

The catalytic converter was probably dealing with the white smoke until it gave out. The bad head gasket was the root cause of all the other stuff. By driving with the check engine light on you aggravated an already bad situation. Here’s some info from NAPA. http://knowhow.napaonline.com/catalytic-converter-failure-3-common-causes/#:~:text=A%20slow%20leak%2C%20however%20—%20say,they%20are%20no%20longer%20effective. Again, the shop dealt with symptoms instead of the root cause. You needed all the other repairs but you also needed to have the head gasket replaced and in terms of cost you ain’t seen nothing yet.

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Ideally they should have identified the true cause of the misfire on the first visit before it lead to complete failure but he total cost of repair would be about he same. Whether or not they will give you a free engine repair will be up to the manager, they don’t have to.

If they had spotted the head gasket leak on the first visit you would have had to pay for all of those parts plus the engine repair, the catalytic converter and oxygen sensors were damaged by driving with a misfire.

On the auto repair information service site that I use there are 255 reports of head gasket failures for the 2011 Xterra.

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Well, not what I wanted to hear, but I thank you guys for taking the time to respond. I bought this Xterra used last July, with 118,000 miles on it. It’s at 128,000 now. When I drove it off the lot for the first time, I got it home an tried to start it-- wouldn’t start. Turns out, right off the used car lot, the Engine Control Module was fried by the time I got it home. Spent $1,600 to get that fixed. I haven’t even owned the car for a year yet and now all of these repairs. Anyway, don’t mean to complain, but this is just very frustrating. I’ve owned 8 cars in my lifetime, and never experienced issues like this with any of them. So with the complaining aside, a general search online says that I’m looking to spend, on average, somewhere between $1,100 to $1,600 to get the head gasket replaced. Does this sound right to you guys? I still owe $11,000 on the vehicle, otherwise I wouldn’t have spent the recent $3,000 to get the vehicle fixed-- I would have sold it “as is” or junked the damn thing.

The labor guide shows 18 hours of labor to replace the head gaskets, I’ll guess a least $2500.

Have the vehicle towed back to the dealer and have the problem check out, could be something else.

The xterra has a 4.0 v6. So you have 2 head gaskets. Like shoes. Left and right. I don’t know anyway a dealer could rig a ecm to work long enough to get home. The odds of it dying the day you bought it? Slim. I would say it’s cursed if you don’t get 24 hrs of use before it dies. I would have bought a used ecm.

I am going to go against the grain here. I would argue that you should have gotten rid of this car the moment you were told it needed $3100 of repairs–even if those repairs would have solved the problem. When deciding if it makes sense to spend money repairing a vehicle, or not, that decision should be based on one thing, and one thing only: the cost of repairs versus the cost of the alternative (typically junking the vehicle and buying a different used car).

If the cost to repair your current vehicle is more than the cost to buy a different used car, which is in good condition and runs well, then it’s time to cut your losses and buy something else. On the other hand, if the repair costs are low enough that you could not buy a decent used car for that money, then it still makes sense to do the repairs, even if your current vehicle is worth way less than the repair costs.

The presence or absence of a loan against the vehicle should not affect this decision. The moment you signed the loan contract, this money became a sunk cost. If (by your own admission) spending $3100 to repair this vehicle would have been unwise had you owned it free and clear, then surely spending the $3100 when you owe $10k is an even worse idea.

I think you are going to have to cut your losses on this thing. If a catalytic converter, two 02 sensors, a coil, and all new spark plugs for this model came to $3100, it is highly probable that having the head gaskets replaced will cost over $3000. Even if you find a cheaper shop (which you should have done anyways when confronted with this estimate), it is unlikely that you will find anyone willing to do this repair for less than $2000, probably closer to $2500. The problem with putting this much money into this vehicle is that the alternative (buying an older used car on Craigslist or similar) is cheaper and probably will get you a more reliable vehicle.

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There’s another few kinks to add to this. Since engine coolant has been getting into the cylinders (and quite possibly before you even bought this vehicle) it also means that coolant can wash the cylinder(s) down. This in turn can cause oil consumption problems due to ring/cylinder wall damage.

Yet another is that coolant can mix with motor oil and diluted motor oil will wash out crankshaft bearings and journals.

A very tough situation to be facing because what if after another 3 grand worth of head gaskets it’s discovered the engine is blowing through motor oil at the rate of say a quart per 300 miles and the engine oil pressure is horrible?
Now you drive something you have invested 6+ grand into and still needs a new engine; bottom line. Wish I had a better and more palatable answer for you.

I tend to think that dealership did not think things through too well. Cat too hot and melted O2s should have had them thinking why before replace.


yet a used VQ40DE engine may be bought for under $1500 including shipping, but I’m not sure how much to budget to have it installed

Sorry but I disagree. What is the OP supposed to do about the $11k he still owes? A “sunk cost”? Is he supposed to default and let it be repoed and ruin his credit? IMHO his best option at this point is a rebuilt engine since as @ok4450 pointed out the current one probably needs lots more work. Years ago I had a Pontiac Sunbird with a bum head gasket and for one head gasket plus all the extra work (one item I remember was a new camshaft) it cost me $2k back around 1990. Today, two head gaskets plus rings plus whatever else could easily run more than the $3100 the OP has already spent.

I want to thank everyone for sharing their opinions on this matter. Quite a bit f sound advice here. If I didn’t still owe $11,000 on the vehicle, then I would have definitely cut my losses and moved on. But the obvious problem is that if I were to try to sell or get rid of the vehicle now, I still will have a big chunk of change I owe to the bank. I don’t like the idea of paying for something that I no longer own.

Now, I’m no mechanic by any means, but I’m assuming that if it was a head gasket problem, then I would have seen signs of it earlier? White smoke prior to the repairs? Overheating of the engine maybe? Everything I’ve read online says that the oil would most likely be discolored (more whiteish) and that there would be a sweet smell in the white smoke that it is emitting. Neither of those are the case. The coolant levels are as they should be. The engine isn’t overheating. The white smoke smells like, well…like exhaust with no real “sweetness” to it.

I have to take it back to the dealership that it was repaired at, because if by chance, it is an error in the work they have done, their work is warrantied for one year and they have to fix it free of charge based on that. If it happens to indeed be the head gasket, then I’ll take it to a different shop maybe. I just don’t know at this point. I have never been in this bad of a situation with a vehicle before.

Can’t say that I’ve ever torn into one of these things but what about the possibility of a lower intake gasket leak? I assume there are coolant crossover passages in those gaskets.
Some of the older Ford small blocks used an EGR spacer block on the throttle body which was liquid cooled. Sometimes the gasket would rot out and bleed coolant into the intake and then on into the engine. This would create white smoke with an initial impression of a head gasket fault.
Just some food for thought.

What about an exhaust gas test kit from AutoZone or wherever. That could weed out a head gasket fault. Could be a cheap way to peace of mind or utter despair in the worst case scenario.


The definition of a “sunk cost” is money that has been spent, which you can never get back. It is therefore 100% correct to say that the entire balance of a car loan is a “sunk cost” the moment you signed the contract, especially when the car itself is worth far less than the loan balance. Insofar as the OP, or any person who finds themselves needing to get rid of a financed vehicle for whatever reason, or is faced with massive repair costs on a vehicle which still has a loan on it, the primary concern should be mitigating one’s losses.

The options are as follows:

  1. Default on the loan, cancel the insurance on the inoperable vehicle. Let the lender repossess the car, risk being sued for a deficiency balance.
  2. Contact the lender’s loss mitigation department to discuss junking the car, while offering to continue making payments.
  3. Contact the lender’s loss mitigation department to discuss junking the car, and settling the debt for less than the amount owed.
  4. Pay for the necessary repairs, even if the vehicle isn’t worth enough to justify the cost, or is likely to continue needing expensive repairs.

For most people, options #1 and 2 are really the only viable options. Many people find themselves unable to afford their loan payments, due to losing their job, even if the car itself runs fine. However, if the car is worth less than the loan balance, there won’t be any way to come up with the payoff amount in order to sell the car. In that case, defaulting is the only option.

Also, most people who purchase vehicles on credit do not have thousands of dollars sitting around to pay for major unplanned repair costs. Furthermore, to the extent that the necessary repairs exceed the cost of the alternative (buying a different used car that runs well) and that ongoing problems with the vehicle are likely, it makes sense to cut your losses, not to continue throwing good money after bad.

I would argue that for most people, option #4 is just not worth the cost. If a person would have cut their losses on a particular vehicle if they owned it outright, it would make more sense, rather than less to cut their losses if they owed a lot of money on it.

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Let’s take your estimate of $3000 for the remaining repairs. The likelihood that the OP can find a reliable vehicle that doesn’t have its own problems for $3000 is pretty small. By your own reasoning, the thing to do is fix the vehicle he has.

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First things first, and that is getting a definitive diagnosis. You can get some clues yourself. Check the coolant level. Is it full? Any sign of oil contamination? Same with the engine oil. Is it full and are there signs of coolant contamination?

Get a diagnosis first, If there was a head gasket leaking it should have been picked up by noting the condition of the plugs when they were changed, hoping for an easy fix.