Howdy,
I bought my '97 a few months ago with a check engine lite (P171 & P174 codes) and rough idle, I fixed the rough idle with a new rubber elbow, 4 new 02 sensors and replaced the plugs and wires. I still have the check engine lite but the engine purrs like a kitten. While doing an oil change and going through some suggestions I found on this site I saw oily scale in my coolant reservoir. I am guessing a blown head gasket. My question is how hard are they to change (may as well do both sides) and will I have to pull the engine to get to them.
Thanks for any advice,

Oh it is a '97 super cab V-6 with over 128,000 miles (odometer stopped working a few weeks ago)

Thanks in advance
Rob

 

There is a test that good mechanic shops do to the coolant to determine if there are combustion gases present,which will let you know if it is indeed a blown head gasket.Find one of these shops and have the test done before going any further!

 

How did the engine oil look when you did the oil change? Was it milky looking or a lighter color? Also another easy check would be looking in the coolant reservoir and look for air bubbles coming up through the coolant. Both of these are easy fast tests to see if your head gasket is blown. If both are good you will need to do a compression test then leakdown test.

 

Thanks for the replies,

BlueOvalFitter,
I will call around tomorrow to see if any of the local shops have a coolant test.

bxstang2000,
As far as the oil, it looked normal and had no grit that I felt. There was a white milky substance around the cap of the reservoir. I changed the spark plugs a couple of weeks ago and other than being excessively worn they looked normal with no major buildup. I have never heard of watching for bubbles coming through the coolant, I will have to try that....

Thanks for the inputs.

Oh, if it turns out to be the head gasket how hard will it be to replace?


Rob

 

A blown head gasket is more like a symptom.....not a problem. The gasket itself isn't that bad......but rarely can the problem be completely fixed by replacing the gasket alone. First, ya gotta figure out why it blew in the first place. Usually it's because something got hot and most likely warped. And, if something is warped.....a new gasket isn't gonna do ya any good........or it could be a cracked head........or, a............but, really, that's getting way too far ahead. An oily film in your coolant doesn't automatically mean engine oil is getting in your coolant. And, milky looking stuff on the filler cap is quite common too.

First, do what bxstang says, and do a compression test on all cylinders.....and pressure test the cooling system. You can borrow the stuff from Autozone and do it yourself. for free. If that checks out, and you're still concerned, have a sample of your oil and coolant tested.

 

The 97's and early 98's had bad intake manifold gaskets. That's more likely to be your problem than head gaskets, and if you don't get it taken care of soon, your engine may hydrolock.

 

Howdy,
I finally was able to finally take my truck in and have someone with more equipment take a look at the truck. And you will never guess what came back. I guess there were more codes in the computer and the one that is giving me grief is a "Bank 1 below efficiency". I guess one of the CATS is not working within specs. The shop did a compression check, a leak down test and put it on some sort of oscilloscope looking thing. They ended up flushing the coolant and put in a leak detection dye for monitoring. So long story short NO BLOWN HEAD GASKET!!! At least as far as can anyone can tell at this point. The mechanic said there was no real coolant in the tank it was just plain water and hadn't been changed in a very long time. So the engine is running smooth and as far as the CAT I will eventually replace it but at least it is not critical to do now.
Thanks for the earlier help.
Rob

 

Find out if your intake manifold gaskets have been changed (if possible). I don't know if you can tell by looking or not ... maybe someone else on the board has an answer for that.

As glc said, your '97 4.2 has a history of bad manifold gaskets and if not replaced, might lead to a hydro-locked motor which can get real expensive to fix.

 

Fairlaner,
Thanks for the advice. I don't believe much maintenance other than regular oil changes was done with the previous owner. Right know the truck is running like a scalded cat, other than the check engine light. I know the rear brakes are shot but who needs brakes anyway?

I will see if I can tell if not I will look into just going ahead and replacing it when I get a chance.

Rob

 

Sounds like things are in good shape. Keep an eye on the coolant level in the overflow tank. If it starts dropping slowly (like a quart every few thousand miles) and you get white tailpipe smoke when it first starts, even on days when it's not very cold out, look hard at the intake manifold gasket. On mine, the white smoke would go away as soon as the motor warmed up, then everything was fine. These are the early symptoms. As other have said, if you wait too long, the gasket will fail completely and hydrolock the engine. I took mine in with about 120K on the odometer with the symptoms I mentioned and sure enough, the gasket was close to failing.