Fireman31 Posted January 23, 2013 Report Share Posted January 23, 2013 Reddish brown Dexcool is a sign that its time for a coolant flush. It doesn't mean that your coolant level is low, it shows that your coolant is starting to break down. It means that your coolant is either old, and/or has been subject to high temperatures.... Quote Link to comment Share on other sites More sharing options...
BLNAWAY Posted January 23, 2013 Report Share Posted January 23, 2013 did you ever find any signs of leaks?? Quote Link to comment Share on other sites More sharing options...
D1SCSS Posted January 24, 2013 Report Share Posted January 24, 2013 Redish-brown coolant is the start of dexcool sludge which is usually caused by prolonged driving with low coolant level... GM has TSB's about this. I guess it depends on the amount of time that the system has been exposed to oxygen. You can service the coolant and it will help.Dexcool is a great coolant when the system level is often checked and replaced during the 150K -10 year intervals. I have seen many GM vehicles with well over 100k miles on the original coolant and the coolant looks brand new. Quote Link to comment Share on other sites More sharing options...
stevet8754 Posted January 25, 2013 Author Report Share Posted January 25, 2013 So my mechanic replaced my intake manifold. He did a smoke test and said it was leaking bad. Now the weird part is on my way to work the light came on again with the same codes. P0171 and P0174. Same as before at this point I have new O2 sensors, new MAF. And new intake manifold gasket. Slightly irritating. My mechanic says to give it a few days. But if the problem is fixed shouldn't it go away? Or is there a break in period for such things?. Quote Link to comment Share on other sites More sharing options...
Blown 346 Posted January 25, 2013 Report Share Posted January 25, 2013 Gaskets dont have a break in period. Unless the gaskets werent put in right or they arent seated all the way in there recess. Quote Link to comment Share on other sites More sharing options...
stevet8754 Posted January 25, 2013 Author Report Share Posted January 25, 2013 I'm having 2 coolant lines replaced next week be cause they are indeed leaking verrryyyy slowly. And my from diff seals are getting replaced along with new fluid. He will be looking into the reason why it is running to lean. So at this point I think it might be as simple as a cracked or bad connection in a vacuum line. I didn't see anything when I did a simple visual inspection of the lines around my motor. But then again I don't have a lift In my back yard. Lol. So hopefully it will get resolved next week. Thanks for your help and suggestions . Let me know if you can think of anything else. More help the better. Quote Link to comment Share on other sites More sharing options...
D1SCSS Posted January 26, 2013 Report Share Posted January 26, 2013 I have seen the plastic Intake manifolds on these trucks warp. GM has a spec on how much is acceptable warpage. I always check this whenever I have the manifold off. These manifolds are like $600! I would say that about 1 in every 5 intake gasket jobs need the intake manifold. I replace about 2-3 a year...Have you tested fuel pressure? Low fuel pressure will also set these codes.... Also make sure that there are no leaks in the air intake after the maf sensor. Quote Link to comment Share on other sites More sharing options...
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