zaidatheZ

recently got a 2004 grand touring roadster, the other week i had some buddies over and we took it out for a rip 5 min down the road, when we got back to my house i parked it. no more than 20 seconds later i realized i didn’t pull up enough so i started the car and it sounded awful was idiling really rough and sounded like a harley chopping. and white smoke coming out the exhaust. the smoke is pearly white (not oil) and smells strongly like ash which’s makes me think it’s not coolant cause i read that coolant smells sweet. my dad who’s been a mechanic 30+ years says it’s a head gasket but i started it the next day and the rough idle was GONE and started like normal still the white smoke. please help me out i don’t wanna put a whole new engine in there if it’s something small!!!!! (only modification is a straight pipe single exit from the resonator) will be responsive and post updates let me know what you guys think!

khnitz

I would suggest as first steps:
1) Is the Check Engine (Service Engine Soon) light on? Is it steady or blinking? Even if it is not currently lit, read the codes and are there any DTCs?
2) A compression check of all cylinders and sharing the readings sounds in order, too.

Good luck!

icer5160

iTrader: (4)

You have a compromised head gasket. My best guess would be that you have a small crack or leak, the effects are not immediately noticeable until the engine is fully warmed up. That would explain differences between cold start vs. warm start. White smoke with a sweet scent/odor is definitely a sign of coolant burning. Sounds like the engine was overheated at some point, maybe the previous owner threw some "stopleak" product in the coolant system to temporarily mask the issue. Sorry to hear this, it's a major bummer. Try not to drive it, depending on how bad the leak is, you could cause major bottom end damage from starting/cranking the engine with water in the cylinders.
-Icer

iideadeyeii

iTrader: (6)

I would take it to a mechanic

bealljk

iTrader: (13)

Yea, compression test for sure … you could do a leak down test too but I think the problem is known.

I’d echo head gasket and exactly what Icer said about hot vs. cold engine.

Are you getting coolant pushing out and into/filling the coolant overflow tank?

Is the engine overheating?

The good news is that (all things considered) this isnt a huge pain in the *** fix. If your father can help you with the work I would take the heads off the car (might be easier with the engine out of the car), replaced the head gaskets, replace the head studs and put the engine back together. I’d blown head gaskets once and in my many rebuilds it has been on the easier and less expensive side of things.

zaidatheZ

so today i started the car after letting it sit for 2 weeks (wanted to keep some charge in the battery) and the smoke was GONE i figured it’ll come back when it reaches temp. it didn’t come back so i decided to take it for a quick drive to see if it would at stops or at higher rpm’s. it never did. it ran fine the whole time and i had no issues it didn’t overheat and the coolant level stayed the same. i’m seriously so confused at this point.

zaidatheZ

yes service light was i on i ran the codes the day it happened and it gave me three
1. timing system off
2. multiple cylinder misfire
3. evap system malfunction
haven’t checked them since but i might tonight because it ran perfectly fine with no smoke earlier today.

zaidatheZ

craziest part to it all is the engine only has 89k on it

icer5160

iTrader: (4)

*EDIT*

After catching up with the most recent updates, I would take it to a reputable shop at this point for diagnosis. Some very odd things happening here. Failed head gaskets do not cause "intermittent" issues.

I just thought of another possibility. Does the car have aftermarket HFC (High-Flow-Cats) on it? I have heard reports (rare mind you), that under heavy load conditions, some of these HFCs can blow out and create some insane smoke shows. You would need to remove the Y-Pipe to verify your CATs' honeycombs are still intact. If this did happen, the exhaust note would change or you would be hearing some metallic noises from the exhaust. Could be hard to tell since you haven't owned the car long and may not quite know what normal vs. abnormal noises are.
-Icer

zaidatheZ

as far as i know and can tell it’s just a straight pipe from the resonator the cats are stock.i haven’t heard anything abnormal and the exhaust sounds like the day i got it. i called my dad and he said that head gaskets are weird. if it’s a small leak or fracture then it’ll act fine some days and some days it’ll be awful and back to normal again. i’m thinking about just replacing the engine with a lower mileage vq because the cost of taking it to a shop getting it diagnosed and then if it is a head gasket replacing it would cost me well over 5k. already got a quote from a shop and the nissan dealership. but replacing the motor will cost me 1100 plus cost of the motor from night owl performance in marietta georgia. but i’m not sure still questioning a lot of things.

bealljk

iTrader: (13)

Soooo…something that should / could be considered is that you have moisture built up in the fuel tank and/or the crank-case of the engine…With summer temp swings it could very well be that you had moisture mixed with your oil and/or fuel …

So drive the car under normal conditions, chase those check engine lights and get them fixed too. If the problem doesnt come back than it was something screwy. Otherwise, what Icer said with taking it to a trusted shop is a good idea and a good first step.

zaidatheZ

yea that’s what i was hoping as well, i drove it last night and it was fine no smoke no power loss nothing. the only thing that was a worry was that before the drive my coolant level was at the minimum level so i added some. after the drive i checked it again and the reservoir was FULL over the max fill line and that makes 0 sense to me.

bealljk

iTrader: (13)

oh boy… that’s a bad sign

when coolant pushes out of your overflow reservoir its a pretty good indication that your head gaskets are breached…

icer5160

iTrader: (4)

It's fairly normal for a small amount of coolant to get pushed into the overflow tank. The coolant expands as it heats up so this is perfectly normal. If you ever do a coolant flush and fill using one of those funnel kits, you will see this happen during the air purge cycles. Let's say you start with the fluid level at the bottom of the funnel neck, After the engine idles for 10-15 minutes and reaches operating temps, the fluid level will rise a good amount and visibly steam (almost boiling, fans kick on to prevent boiling). I recently went through this process on my daughters 2006 Honda Civic and I noticed about a 2-inch difference in fluid level from start to finish after the final topping off (to be clear final top-off means after thermostat opened and I added additional fluid). Not all cars are the same, different capacities and coolant types, but in general you will get expansion from the heat, hence the need for an overflow tank. I suspect you may have just overfilled your coolant slightly. Take note of how far above the MAX fill line you are when warmed up. Let the car cool off and just remove that amount from the overflow tank. Run the car again and check level.

What is abnormal, is if you see/hear a lot of bubbling and/or smoke in your coolant reservoir. Also if your reservoir starts to look dirty inside or coolant starts to change to a dark color. Under normal conditions, the overflow tank will slowly/gradually begin to fill up as the engine warms up. If combustion gases were mixing with your coolant from a large leak, you would see some rapid activity (bubbling and such) at the overflow.

Hope that makes sense/helps.
-Icer

bealljk

iTrader: (13)

Very true Icer … good observation and fair point …