Found out I have a small head gasket leak today in my 07 6mt with about 80k miles.

How much more labor would it be to rebuild the engine on top of the head gasket being replaced?

I'm torn between selling the car or replacing the head gasket and replacing the Pistons rings/rebuilding.

Any advice is appreciated.

 

It's not cheap or easy to rebuild or replace the head gasket. Assuming you are doing the work yourself it's probably $350 if you are ONLY replacing the gasket and getting the heads planned. However, there is a lot of stuff you probably should change while you're that deep in the motor like the timing chain and water pump.

If you're going as deep as rings/bearings and doing a full rebuild it can probably be done for as little as $2000 again assuming you do all the work yourself except the machining and bargain hunt as much as possible.

If​​​​​ you've never rebuilt a motor I would definitely not recommend learning on this one. Just buy a long block and swap. You can probably eBay or jdm import a 50k used motor for $2500.

 

That's what I figured. Time to strip the mods and look for another g35/350/g37

 

Was the motor burning oil regularly prior to the head gasket blowing? What % would you say the car has driven on the highway vs city-traffic type driving?

How attached to the car are you and how much do you like the car in general?

80K miles is pretty low for any modern motor car and if it was running good aside from the head gasket issue, your loss might turn into someone else's gain if you sell the car. If your motor wasn't already burning a noticeable amount of oil and your car hasn't lived an excessively abusive lifestyle thus far (in terms of racing and nonstop city driving with lots of hard acceleration), I would probably just replace the head gaskets on both sides and the water pump. If you plan on keeping the car you probably should also replace the timing chain guides and tensioners (the chains themselves are probably OK but you may want to just replace those too while you're in there since they usually come as a kit), This is an extremely labor intensive job though, so if you are paying someone else to do it you'll definitely want to factor that major labor cost into your decision. Parts and materials alone are going to run you a solid $500+ if you use OEM quality parts and replace both head gaskets (which you definitely should), all 3 chains, tensioners, and guides along with the water pump and other little gaskets that you may encounter along the way (usually for things like cam phasers, etc).

I really haven't heard of many non-boosted VQ35's blowing head gaskets. Are you sure your problem is really a blown head gasket and not worn rings or something else? A lot of people with the Rev-Up VQ35's like you have run into this issue around the 80-100K mile mark.

 

Thanks for the response. Could worn rings lead to exhaust in the cooling system?

About 37k miles have been hard city/track miles. On the highway she uses about 1/2 quart in 800 miles. During hard use it'll use 4 quarts during 800 miles.

I am quite attached to the car but the transmisson isn't as great as it used to be, has been outside so the body isn't great, and needs new controls arms, compression rods etc.

 

Time for a completely rebuilt or used motor with that kind of OC. And with a used motor there's probably no way to tell if it has the OC or how bad it is. Sorry that's probably not the news you were wanting to hear.

 

Scrap that motor.... thing's junk.

 

How much does it run to rebuild the rings and pistons? (obviously would mean rebuilding the motor) Would it be a huge price difference rebuilding with oem parts or going with after market rods and pistons/rings?
How familiar are most shops with rebuilding DE motors?

 

Whatever the cost it is not worth sinking all that money into a ten year old vehicle.
Find another vehicle that runs

Just my $.02

Telcoman

 

Best Advice: fill the pan with 20/50 weight oil, run it thru the car wash and trade it in! No use throwing $$ on a car that has other issues along with burning oil! This is the perfect time of year to get into a new ride, manufactures have new models coming out soon!
Gary

 

20/50 so she drinks less oil?

 

Thicker viscosity oil can make a worn motor much quieter, slight knock and noise can be temporarily eliminated (read HIDDEN). It will still make it past the rings (not as bad as stock viscosity) if they are worn but by the time the rings are worn there's usually noise associated with it and this will cover up a lot of the sound. I've owned a lot of higher mileage vehicles and usually increase the viscosity slightly when they hit the 150k mark, my Sierra 2500 has 280k on it and still runs like a champ on 10w-40 (stock oil is 5w-30).

EDIT: Thicker viscosity also increases oil pressure in case you are getting low pressure warning lights.

 

Thanks! Makes sense. Fortunately she's not knocking yet. I really don't want to ditch my problems on someone else, so I'll probably be up front about the compression test and head gasket leak.