MNorlander

oops- I had this posted in the wrong forum. Now it should be good.

What: Ok so my corvette has some problems running lately, regardless of rain.

Problem: Progressively gets more and more grumblish/sluggish. Seems the engine is firing and I'm not picking up any speed, or that it's misfiring. ie. Today I woke up and dropped off some books at the library, on the way over, it was GREAT. on the way back, I noticed it would start missing(notice this during certain parts of acceleration and when idling it becomes really rough). Then 5minutes after I got home I left to pick up my check, and it became quite rough. When accelerating it would seem to intermittenly grumble, then catch for a bit, etc

What I know: The coolant leaks. I put in new coolant Monday, and it is already down about a quarter inch on the reserve.
It blows smoke out the back after I start it up and it's been sitting for a while. ie: this morning it blew smoke up, then ran great for first 5minutes. the 2 second times I started it up there wasn't much if any smoke going out the back, but it ran a lot worse.
Also to note a hose to the reserve blew about a month ago, but my dad repaired.

Guesses: Maybe the coolant leaks somewhere into the head gaskets? I'm really stumped. My dad thinks it's electrical/fuel injection, but because it seems to get progressively worse as it 'warms up' and it has these problems regardless of rain, I tend to think it is not.

nutz4c4

Coolant down? Any visible leaks? What color is the smoke? If you don't have any visible leaks then you should pressure test the cooling system to find out where the coolant is going. Any condensation inside the valve covers or on the dipstick that looks like mayonaise?

MNorlander

No visible leaks. The color of the smoke is white. There is nothing on the dipstick that looks like mayonaise, I haven't checked inside the valve covers.

nutz4c4

White smoke isn't good my friend. Sounds like a bad head gasket or cylinder head warpped or cracked. Have you ever overheated the engine?

MNorlander

I have never knowingly overheated the engine.

However this might be relevant: I bought the car on 10/21. I was not aware that the coolant leaked. early November a hose to the reserve coolant broke, and my dad repaired it. We never filled it up again. The past week I had noticed low coolant light, Monday I refilled it. When I did, the reserve was empty and the main was about 4" down.. thankfully I drive about 1mile to school, and about half a mile to work. Haven't taken it on the freeway since the hose blew and it has been winter. However I have not noticed a significant increase in performance since refilling. It is still the same old progressively worse after sitting for a while thing.

nutz4c4

First thing to do is get a pressure test on the cooling system. This will give some insight as to where the coolant is going. You should do this as soon as possible. I personnaly wouldn't drive the car until it's checked out and repaired so you don't cause any more damage to the engine. It may only be a minor problem...but on these cars even minor problems are a PITA. Get it checked out ASAP.

MNorlander

Thanks. I will head over to a mechanic I know tihs afternoon and see if he can do that. Hopefully won't empty my pockets

nutz4c4

Good luck

MNorlander

On another note I always watched the coolant temp and starting up it was always around 130 and never got past 210

nutz4c4

At start up your display should read LO.You may also want to get the sender checked out for accuracy.

AZC4Guy

no codes? plugged cats? EGR?

Frizlefrak

Any time you let a mechanic touch your Vette, plan on being bent over. There's a reason most of us do our own wrenching, and it isn't our love of bloody knuckles.


Like Nutz said, white smoke isn't good. Generally indicates coolant is entering the combustion chamber. And since you're losing coolant.....

Pressure test the cooling system. Also, pull your plugs and look for a fouled plug or two. This will tell you which bank has spring the leak. I'm betting your performance issue is due to fouled plugs that the coolant has done a number on.

And, if your head gasket is blown as I suspect it is, the engine may be down on compression on at least one cylinder, which will make it run funky too. Run a compression test and post the values.


If it is a head gasket, it really isn't that hard to replace. A good afternoon job.

Good luck....

MNorlander

I told him to pressure check the coolant system. About a month ago when this whole fiasco started developing my dad and I checked the spark plus- they seemed fine. He even called his brother who builds engines for fun and described them to him and he said they shouldn't be the problem.

I'm sure the mechanic will also do a compression test.

Talking with my dad he said a head gasket isn't expensive itself, but it costs $2000 in labor to do it; you say it is an afternoon job?

could you further yourself?

John A. Marker

My "guess" would be intake is leaking. If you do a compression test and all is good, then the head gaskets are okay. If you have never done gaskets before, figure a day to tear down and put it back together. Just be sure to label EVERYTHING and take pictures so you can be sure to get all hoses and wires back where they were.

If you decide to do it yourself and need a hand, contact me. I am moving my shop (metal shop) in January, but might be able to work around your schedule.

VetBoy89II

A head gasket set on your car shouldn't cost more than $100 (I can check tomorrow at work to verify), you HAVE to replace the head bolts which, depending on where you get them, cost around $100 give or take. The rest is all labor, including sending your heads out to a machine shop to test them (about $100-$200) and then it's about a 10 hour job if you know what you are doing and have the right tools and equipment to complete the mission. I believe (off the top of my head) that book time on a head job is 14 hours labor plus parts, so expect to pay that much to a repair shop if you take it in; depending on their labor rate you're looking at $1500-$2000. It's not a difficult task if you know what you are doing, BUT if you really don't know what your are doing, ONE small "fork" up and you can be looking at spending 1,000's of dollars on a new motor.

If you decide to do it yourself, you definately want to buy a FelPro Head Gasket Set and ARP Head Bolts ... don't skimp here, they are not that much more expensive then the cheaper brands and you won't have to worry about kicking yourself in the long run because you saved $50 or so.

Anyway, check your car out in this order ...

1) Check your RADIATOR, especially along the side tanks. Check your radiator cap also.

2) Check ALL of your hoses, make sure the clamps are on secure, not too tight though, you don't want to rip a hose. On that note, make sure none of the clamps are already not too tight and possibly already ripped a hose.

3) Check your thermostat housing, after checking where the hose connects, check where the bolts mate to the intake and then the thermostat gasket area.

4) Check you water pump, you have a "weep hole" in the snout, if it's leaking you should see remnants of a dried (or wet) waterfall around the base.

5) Check all around your intake manifold especially to the rear of the engine, they are notorious for leaking on the back deck.

6) If you don't see anything after all that and if you feel comfortable pulling plugs, you can try this method: Unplug your distributor power wires (NOT the spark plug wires, but the wire connectors attached to the distributors side/bottom). Then pull ALL of your spark plugs, have somebody stand by the front of the vehicle (off to the side if it's a manual transmission for safety purposes), now crank your engine 3-4 times, usually if you have a blown head gasket, water will come spraying out of one or adjacent two spark plug holes (oh, BTW, don't have the person watching stand to close to the engine, the water REALLY can spray out with force ) IF you have water spray out, it is DEFINATELY a blown head gasket, IF you DON'T get any water, you can't rule a head gasket out because it could be blown in a different area of the head (but that would take too long to write about right now )

As for the running rough part, things are pointing to a bad head gasket or intake gasket, but you really need to look at the tuneup stuff a lot closer. Have you checked your cap and rotor? ALL of the plugs, or just one or two? Spark plug wires? They have a nasty tendency on our cars to rub up against the exhaust manifolds and burn through enough to cause a major miss (ONE bad wire on our beasts and it feels like she's running on only 4). You may simply just have a compound issue of having a coolant leak AND needing a tuneup.

So try these methods first before you take it to the repair shop because they are gonna charge you at least 1-2 hours labor just to do the coolant pressure test and compression test. At least rule these things out for yourself first.

Let us know what you find, we'll take it from there ...

[Edited to say]: Heck man, I just realized you were in Pleasanton, I'm in San Jose, if you need a hand, don't hesitate to ask.

REDC4CORVETTE

I would do a compression test FIRST ,if you have no coolent leaks.

hippy

What you haven't been told here is that head gasket/head issues CAN BE DEPENDANT ON MOTOR TEMPERATURE.
You can do a compression test and come up OK, you can pressurize your cooling system and be ok. Until you run the motor thru it's operational temperature you may not know if the heads or gaskets are an issue. Probably the best test to do is an exhaust gas test of the coolant while the engine is running and going thru its temperature ranges. If you are doing the work yourself I'd do the compression and cooling system pressure test first. If not tell your hired wrench to do the exhaust gas test 2nd after pressurizing your cooling system.

cv67

Good tip, Hippy.

Has anyone checked to see if it threw a code?
Tested injectors?
Test the MAF?

Dont pull the heads just yet..

hippy

What color was your smoke?

VetBoy89II

Was it smoke or was it just steam from being cold outside in the morning? Next time it does it, take a whiff of the "smoke", you can definately smell the difference between typical exhaust that is steaming from the smell of coolant blowing out the pipes.

To check the "mayonaise in you valve covers", take off the cap where you add oil to your car, look under it, it may not be as thick as mayonaise, but it may look more like a tan or creamy colored milk residue under that cap.