3.7 Inline 5 - 08 Colorado - replace engine heads?

sfarag21

Newbie
Forgive my noobness. I have an 08 Colorado with the 3.7 I5 engine and about 92,000 miles. Recently I got two error displays. First the ABS Fault light came on and then the engine light came on. I took the it into the dealership to see what was wrong.

After a lot of searching and mystery they told me:
1. Error Code Ro300: The # 1 cylinder has low compression and needs a new head. The guy said I need to do all the heads to the tune of $2,300.00.

2. the ABS fault display is coming on because both front hub bearings and wiring harnesses need to be replaced. The dealer wants $1,300.00 for this.

Does anyone have any experience with either of these this? If so, how much should it cost to fix if I go new parts or rebuilt parts? Any advice would be welcome. Thanks!

sfarag21
 

mrphoenix80

Active Member
1.) the code P0300 is for an engine misfire. The Colorados have had issues with the valve seats and valves leaking, There is a TSB to do a leakdown test to determine if this is the issue. If it is valve leakage then you should replace the head assembly as per the TSB. However this is an isolated issue I think I have only seen 2 or 3 in the last few years. Being that the truck is under 100k miles you could call GM to see if they can help you out any, even if they do a 50/50 split its better than nothing. However there are other things that can cause a misfire clogged injectors or worn plugs. I would ask to see what kind of test he did to determine the head is at fault.

2.) as the for ABS problem without the codes I have hard time giving you advice. The light can be caused by a large number of items. GM hubs can be expensive and on top of that the hubs and sensors come seperate. If someone put in an aftermarket hub with a GM sensor sometimes they don't play nice. If I cant tell I would recomend a hub and sensor. I have had good luck with aftermarket hubs(for some reason they come with the sensors) at a huge cost savings over OEM.

I hope this helps
 
sfarag21 said:
how much should it cost to fix if I go new parts or rebuilt parts?

I used to have a Colorado and Canyon with the I5. Your best bet is to have multiple places look at it to verify the head is the problem. A p0300 means multiple cylinder misfire. Cant see how they came to that conclusion just checking cylinder 1.

$1300 is way too much to replace a hub. I dont care if its an oem item or not. Get another opinion.
 

sfarag21

Newbie
Thread Starter
mrphoenix80 said:
1.) the code P0300 is for an engine misfire. The Colorados have had issues with the valve seats and valves leaking, There is a TSB to do a leakdown test to determine if this is the issue. If it is valve leakage then you should replace the head assembly as per the TSB. However this is an isolated issue I think I have only seen 2 or 3 in the last few years. Being that the truck is under 100k miles you could call GM to see if they can help you out any, even if they do a 50/50 split its better than nothing. However there are other things that can cause a misfire clogged injectors or worn plugs. I would ask to see what kind of test he did to determine the head is at fault.

2.) as the for ABS problem without the codes I have hard time giving you advice. The light can be caused by a large number of items. GM hubs can be expensive and on top of that the hubs and sensors come seperate. If someone put in an aftermarket hub with a GM sensor sometimes they don't play nice. If I cant tell I would recomend a hub and sensor. I have had good luck with aftermarket hubs(for some reason they come with the sensors) at a huge cost savings over OEM.

I hope this helps

Thanks guys! with respect to the brake code, they wrote down a bunch of codes. The main one I think is C0035 (circled). They wrote a bunch of other codes though: UI064, C0899, C0035. I'll call the dealership again to see what exactly they did to test the head.

I've been reading a lot online about this issue. It seems like a lot of people have had this problem after getting their brakes done (including me). I keep reading about people replacing the hubs and having the problem reoccur (after wasting a grand or two). I complained to GM and I am waiting for a response. I doubt they are going to do anything to help. The only other "symptom" I get is push back on the pedal under my foot when I break occasionally. There is no real noise that comes or goes, one of the rotors is scratched so I get a little shimmying when I brake. I have very little faith that the dealership knows what is wrong... They charged me $120 to inspect it to ... I'll take it in for another opinion as well. :confused:
 

mrphoenix80

Active Member
As far as codes go 99% are formated with a letter followed by 4 numbers. The first letters are, P for Powertrain, C for Chassis, B for Body, and U for data communication. There are a few exceptions where they put a alpha character in the 3rd or 4th number position ( P02A1,P02ADor P040D) however these are mostly used in diesel trucks. Also DTC's often include a symptom code for example C0035 sym 00. Those extra digits tell the difference between an open or intermitant. OK enough genaric info about DTC codes

So now for your codes...
U1064 loss of comm with the BCM) Often these codes can be dismissed if you are not having major issues. For example if the bcm went down nothing would work right from turn signals to the odometer.

C0899 low system volts) Often caused by low battery power. So if it is a history code ignore it

C0035 LF speed sensor circuit) this code has a sympton code to go with it but for the moment it is not that important.
So we have a problem with the LF speed sensor. Judging by the symptoms you are talking about you have a intermitant sensor. I have had this problem with several customer trucks also my father and landlord's trucks. The way I fixed it was to replace the wheel bearing and sensor as an assembly. Because unless you know what parts you have, you have to remember that GM and after market parts don't always work well together. Another side is that for what you would pay for a GM sensor(without bearing) you are close to the price of an aftermarket assembly(with bearing and sensor).

But before you go all crazy and replace the assembly. Check the back of the hub. It is open to the world and sometimes a piece of rust could get in there a really mess with ya.

Also there is a TSB #PIT3460Q that states to have the tech check the the data in the ABS unit to determine which hub is bad. I have seen this bite a coworker in the :lipsrsealed:!!!! He put in a LF hub because that was the only code. IT DID NOT FIX IT! After that we found this bullitin. It only applies to Colorado/Canyon trucks. In the data menu "Event History CAL data 5" will have numbers in it. These will tell you for sure what to do. For example 0=no problem,1= RF,2=LF,3=LF+RF, on up to 7.

The rotors are captured meaning they are between the hub and knuckle. So you have to remove the hub to replace the rotor. So if you want to change the rotor, do it when you are replacing the hub. I was also told by GM tech assistance the internals of the sensor are ceramic. The point the guy at TAC was trying to make was not to hammer the sensor on to the hub because you will break it. In my mind if that will break it, then beating the crap out of the hub to get it out to do a rotor does not seem to be a good idea either.
 

rjpoog1989

Registered Member
mrphoenix80 said:
1.) the code P0300 is for an engine misfire. The Colorados have had issues with the valve seats and valves leaking, There is a TSB to do a leakdown test to determine if this is the issue. If it is valve leakage then you should replace the head assembly as per the TSB. However this is an isolated issue I think I have only seen 2 or 3 in the last few years. Being that the truck is under 100k miles you could call GM to see if they can help you out any, even if they do a 50/50 split its better than nothing. However there are other things that can cause a misfire clogged injectors or worn plugs. I would ask to see what kind of test he did to determine the head is at fault.

The head seating issues were limited to the 2004,05,and 06 models and corrected in the year 2007. His being an 08 it should have the updated head design.

That being said, if the head needs replaced, just buy a new engine with less miles, it might be cheaper... Definitely get a leak down test performed and a second opinion from another shop.

I posted about ABS fault in your other thread.
 

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