I have a 2002 4x4 blazer with roughly 80,000 miles. I recently had taken it into a shop to have them look at a few problems I was having which turned into my transmission needing to be rebuilt -- believe me, I was not happy because rebuilding the tranny still did not address the problems I was originally having with the truck. My mechanic who was working on the truck told me that I have a coolant leak in the intake manifold. My Service Engine Soon light has been on solid long before I had the tranny rebuilt, and it still remains on. I have to use the expressway to travel to work everyday (however now I am using a different car until my truck is fixed), and the SES light has a habit of going from solid to flashing whenever I drive at higher speeds. I now know this is because of the leak. Additionally, whenever I had taken my truck in to get the codes read for the SES light, it was always the same coolant code.

My question is I know this is at least a 4 hour repair job, but is it something that should be worked on in the shop or is it something I would be able to handle myself? Also, could there be something else wrong on top ofthe leak in the manifold which is causing me problems?

I would GREATLY appreciate any help you can offer me. I'm trying to get these problems taken care of asap considering Michigan's winter weather is not exactly 'car friendly'...I need my truck.

Thanks again!

 

Where is the leak? Is it a coolant leak or a vacuum leak? I'll assume coolant, but is it leaking into the cylinder or into the oil or out to the exterior of the engine?

A flashing SES light means that there is a misfire that could result in permanent damage to the motor.

What was the specific code?

 

I'm not sure where the leak is just yet. All I know is that there is a coolant leak in the manifold. I plan on taking my truck into the shop just to have them let me know what's going on.

When I last had the codes read, I believe it came up with P128. It was a coolant thermostat problem from what I remember, however that really didn't make any sense to me. My thermostat was working properly. Although, the problem could also be in the ECT wiring/sensor.

As far as the flashing SES light goes, does that mean that there could be a fuel problem and that I should get the fuel filter replaced? Or, does that mean something completely different? I have been getting mixed advise when it comes to that. I did replace my distributor cap about a month ago. What else could be causing the misfire?

 

There are a number of things that can cause a misfire. Fuel supply, spark (intensity & timing), or lack of air. Now, the ECT may be causing this if it is reading incorrectly and causing a rich condition. This is where reading your plugs would let you in on what is going wrong. Also, if your mechanic has a scan tool capable of seeing the long and short term fuel trims for each bank, that would help too as the O2 sensors should be telling the PCM to lean out the mixture, but they could be getting overridden by the fact that the PCM thinks the engine is still cold. A fully compliant scan tool that can read sensor data would also be able to look at the ECT value being fed to the PCM and determine from there if it is just a bad sensor or something else going wrong.