Car Questions

Clear all

[Solved] Connected coolant line to evap


Topic starter

My 2008 Nissan Maxima SL 3.5 V6 automatic tranny is fully stock. It has 125k miles and I noticed a rough idle, so I decided to change the spark plugs.
Once changing the spark plugs, I decided to change the coil boot (and spring) and the plenum gasket as well. 
When I started my car again, I immediately got a few codes, which I cleared. Two of the codes were p0223 and p1217, I'm not sure what the 3rd was. 
I drove the car for a mile (prob made it up to 30 - 40 mph) and all was fine. The next day, I drove it to work - around 5 miles. After 4 miles or so, I gave gas and it took a second to register, but once it did, I was driving ~40-50 mph A mile later, at a red light, the car started idling very roughly. After I turned, it started jumping very roughly (I'm gonna take an uneducated guess that everything was misfiring) and was just getting worse. The tachometer was bouncing up and down, I barely rolled into a parking spot at work. After work, I cleared the codes and tried driving again, but the car was really jumping. Then I started hearing popping noises from the engine area, so I pulled over and towed the car to the shop. At this point, the car had a p1217.
when the mechanic got around to looking at the car few days later, it wouldn't start.
He took off the 6 spark plugs and they looked fine, he put everything back together and it worked once again. He told me he ran it for while and no CEL. I found p0113 and p0300 pending and I brought the car right back into the shop. After looking some more, he realized that I plugged a coolant line into the evap line (and vice versa). He put the hoses back in the correct place and cleaned out the carbon filter. The car ran, but not very well.

It was randomly shaking hard when driving. I had pending misfire codes (p0301, p0302, p0306, the other 3 cylinders may have also been pending at some point and I didn't catch it) and a CEL from a p0300. I cleared the codes and drive some more. Also, sometimes the gas pedal was unresponsive.

Then, the CEL started flashing. I pulled over, shut off and restarted the car and the flashing stopped. I later took it on the highway and drive 75 MPH mostly without feeling anything strange. 

I let the car for for a week and then started it up. The batter was dead, not sure why. Would idling without driving do that? When it started up, besides the misfiring, after a few minutes, the was some smoke. Seemed to be very light gray with perhaps a tinge of blue - it was nighttime and was not easy to make out the color.

 I lifted the back seat and pumped out all the gas. At the bottom of the tank, I found what appears to be antifreeze, whiff I think would explain everything. I really don't think the spark plugs themselves were the issue, although perhaps they got mucked up by the coolant. Here's a picture of the coolant looking liquid from the bottom of the tank.

​​​​​​​​​​​I didn't get every single droplet of gas out, there was still a few ounces of gas left, some of that was probably coolant.

I added a 4 gallons of gas (93, without I usually use regular) and a bottle of Iso-Heet. When I started up again, it was still misfiring. I noticed that there were drops of water dripping from the exhaust, like 1 deep a second. I plugged in my BlueDriver and got a pending p0306 and a p0300 which type the CEL again. This is the freeze frame report from the p0300:

I figured I'd check cylinder 6 to see what the spark plug actually looked like. This is the brand new plug after ~20 miles of driving. (I didn't check the others.) I also looked into the bottom of the cylinder and it looked pretty dirty.

I'm thinking that I should change the fuel filter before trying again. I don't know which filter to get since I think the OEM version only comes as part of the fuel pump assembly. I also don't know if there's anything else to do.

I certainly learned (and still learning) a ton more about cars and how they work from this experience!

My friend told me I should just drive it until it's better, but that flashing CEL is starting and stopping and making me nervous so I don't wanna drive it.

2 Answers

Ok, water doesn’t compress. It’s possible you may have done internal damage to your cylinders. Also fuel filters swell, and fuel pumps rely on gas to lubricate them. You really need to drop your fuel tank, clean it out. And replace the OEM filter. And while you are in it I would just go ahead and do the pump. Before you do all that, you need to run a head gasket test, make sure it isn’t blown. Head gasket test kit can be bought online for about 20 bucks. Also do a compression test make sure engine internals are ok first. 

If the fuel filter in the tank was exposed to antifreeze and water for any length of time it is trashed and will restrict fuel flow. 



I would actually recommend you start hunting for another car.

Who knows what has got damaged in the process & if it’ll turn into an endless money pit, shortly. 

I’m actually mind boggled. I don’t recall ever seeing a coolant line and evap line the same size before.

Human factors..

Thank you. I'll work on it, first gonna buy another car. Looking for an Accord or Camry for $7k-ish in NY area. Kinda hard to find something decent.

Eventually, I'll get around checking the head gasket and if good, dropping the tank. You think a few ounces of antifreeze warrant that? That seems like a pain to do in my driveway.

The lines look more or less the same size to me. But my human factor certainly kicked in 😲