Multiple issues plaguing my '96. Two of the biggies...

[SteveRosenow]

Yesterday afternoon I experienced a profound loss of power after fueling up at a gas station. As I began pulling out onto a local highway, I had to floor it to gain speed and it seemed the harder I floored it, the more power I actually lost.

A few days prior, I took it to my work (I work at O'Reilly Auto) and used our OBD-II code reader on it. The following codes were thrown:

P0402 EGR Flow Excessive

P0171 System Too Lean Bank 1

P0174 System Too Lean Bank 2

The day before, I took out the EGR valve and soaked it in intake cleaner to remove the carbon buildup, then used a steel wire brush to remove the rest. At the end of doing that I had an EGR valve that looked fundamentally new. So I'm confused as to why the EGR valve excessive flow is present.

Secondly, this loss of power is most profound when going uphill after a dead stop.

What could be the cause of this? I am not of great financial means at the moment.

Secondly, when I was driving yesterday back from town, I noticed the heater was blowing cold air in spite of the coolant system being nearly full. Three years ago the radiator was replaced. Last week I took it to a pressure washer and power-washed the engine bay while I was detailing the SUV as a whole.

Ever since, I've noticed a maple syrup smell coming from the front left side of the radiator (viewed when looking at the vehicle) and a puddle that develops underneath it. The kicker is that the side tank is relatively dry.

What could be causing this? I hope it's not a blown head gasket.

For information and disclosure, it's a 1996 Ford Explorer XLT 5.0L V8 AWD model.

 

[masospaghetti]

Maybe you were too aggressive while you were cleaning the EGR valve? Did it have the P0402 code before you cleaned it? The P0171 and P0174 sounds like a leak somewhere on your intake causing air to bypass the MAF and throttle body.

The "maple syrup" smell is a coolant leak. Rent a pressure testing kit (I've gotten mine from Autozone, but O'reilly's might also have it) as a loaner and see where your leak is. They are hard to pinpoint without the kit since the leaks tend to happen when hot under pressure, and hot coolant will evaporate off and often travel before it drips.

The heater not working may be lack of coolant, a bad coolant diverter valve, or bad blend door. Find the leak, make sure the coolant is full, and go from there.

 

[SteveRosenow]

Maybe you were too aggressive while you were cleaning the EGR valve? Did it have the P0402 code before you cleaned it? The P0171 and P0174 sounds like a leak somewhere on your intake causing air to bypass the MAF and throttle body.

The "maple syrup" smell is a coolant leak. Rent a pressure testing kit (I've gotten mine from Autozone, but O'reilly's might also have it) as a loaner and see where your leak is. They are hard to pinpoint without the kit since the leaks tend to happen when hot under pressure, and hot coolant will evaporate off and often travel before it drips.

The heater not working may be lack of coolant, a bad coolant diverter valve, or bad blend door. Find the leak, make sure the coolant is full, and go from there.

Yes, the P0402 code was thrown before I cleaned the EGR valve. In fact, before I started working for the local O'Reilly here I had taken it in to have the codes read and there were 13 repeated instances of that code. I was told by someone who knew a bit more about these things that the most common cause for P0402 is a clogged/stuck EGR valve so that's why I cleaned it.

 

[XLTrunner]

I would tend to agree the smell is leaking coolant. Also, if it were me, I'd seek out the closest U Pull yard and grab a used EGR and try it if you don't want to spend the money for a new one. The acceleration issue could be attributed to something you did while power washing the engine bay. You should NEVER use a high pressure spray to clean the engine. Too many electronics in there that can be compromised with water penetration.

 

[SteveRosenow]

I would tend to agree the smell is leaking coolant. Also, if it were me, I'd seek out the closest U Pull yard and grab a used EGR and try it if you don't want to spend the money for a new one. The acceleration issue could be attributed to something you did while power washing the engine bay. You should NEVER use a high pressure spray to clean the engine. Too many electronics in there that can be compromised with water penetration.

I had the acceleration issue long before I did that, though.

 

[SteveRosenow]

Today while attempting to replace the PCV valve (which ended up in an aborted attempt as it's too difficult to reach for now, and losing a 10mm socket down onto the intake somewhere in an irretrievable location ), I decided to have a look at the heater control valve.

Has anyone ever bypassed these with a two way barbed fitting? Mine is badly worn and doesn't open completely. I suspect that is partly why I have intermittent cold air when driving. I also noticed that my temperature gauge fluctuates somewhat when it starts blowing cold air, too.

What could be the culprit? I have tried purging as much air out of the system as I can. Not sure where to look next.

 

[fast_dave]

I decided to have a look at the heater control valve.

Has anyone ever bypassed these with a two way barbed fitting? Mine is badly worn and doesn't open completely.

@SteveRosenow

You work at O'Reilly

To properly purge the system of air, help yourself out by purchasing a new heater control valve - $6 for Aftermarket to $18 for Factory

Link for Examples: 1996 FORD EXPLORER 4.0L V6 Heater Valve | RockAuto

Install the new heater control valve.

Ensure Coolant Overflow Tank is 1/2 full of 50/50 Coolant.

Remove the radiator cap.

Turn heater control setting in cabin to FULL HOT to allow coolant to circulate into heater core (and purge out air)

Start Explorer (outside) and bring up to Operating Temperature with the radiator cap OFF.

Vary Idle Speed to purge air from system for approximately 10 minutes (air & HOT coolant will "burp" out from spot where radiator cap goes as the system purges air).

Turn off engine.

Put Radiator cap back on and twist closed.

As the engine cools, the vacuum created by the radiator cap being installed will suck in 50/50 coolant from your coolant overflow tank. This is what you want to occur!

Wait an hour or so, and refill 50/50 coolant into the coolant overflow tank up to 1/2 full level.

Watch coolant level over the next few days as you daily drive, and try not allow the level in overflow tank to go below 1/2 full.

Hope that helps !

Watch

 

[XLTrunner]

I'll add one more thing to Fast Dave's post...get the front end up in the air a little to help the air escape (air rises to the highest point) while the radiator cap is off and engine warming up. Been doing this for decades on my vehicles and have never had a trapped air problem.