Dirty cooling system and pinging

[Falcon_LS]

I had a detonation problem with my Grand Marquis ever since I bought the car, which I've mentioned many times on here. After running the UK version of STP's Complete Fuel System cleaner and a dose of 50 ml TC-W3 to 150 ml MMO, it's gotten considerably less. But subject the engine to load, such as WOT, and the dreaded pinging was still there. Sometimes I think it's gone for good, but it just keeps coming back!

Considering how dirty the cooling system is (pictures of the old "coolant" filter), even after replacing the coolant multiple times, last week I decided to try the dishwasher tablet trick. The coolant capacity is 16L, so I crumbled one tablet and threw it in the reservoir when the engine was at operating temperature after a 35 minute drive. Over the course of the past week, the coolant has gotten considerably darker and if I was to extract a sample, it looks almost like coffee. So I'm going to be flushing it out rather soon.

But I also noticed two other things. The coolant temperature gauge reads slightly lower and the pinging is reduced. It's still there under WOT, but doesn't last as long as before and you have to really pay attention to it. My understanding is that the engine was running slightly hotter than it should have, which may have been the cause of the pinging. Would this be a correct assumption?

 

[panthermike]

Not sure what type of coolant you use, but have you ever thought about Water wetter or Kool-it? That could help.

I only mention coolant type because I've heard some say that certain coolants +WW can cause a grime.

 

[Falcon_LS]

I'm using Motorcraft G-05 (50:50 mix with distilled water), although the previous coolant was factory fill mixed with ACDelco Dexcool when the water pump was replaced.

Unfortunately the WW or Kool-It is a no go, simply because it's not available locally and it's quite difficult to get liquids shipped across.

 

[gomes512]

What was happening and may still be happening is that the grime is creating "hotspots" in the system.

I've had good luck with the commercial cleaning kits on units that we're gummed from Dexcool.

 

[chevrofreak]

Run a lower temperature thermostat. I have a 180 in my 96 crown vic and it runs great, and the detonation is quite a lot less than it used to be. I also replaced my MAF sensor because the barometric pressure reading was lower than it should have been for my elevation, which contributed to the detonation.

 

[mechtech2]

If the gas octane is up to what the car specs, then a problem could be running too hot, or advanced ignition timing.
An EGR system could be faulty.

I am hesitant to run a cooler thermostat, but a 185 could help.

 

[Scott_Tucker]

Have you tried running premium fuel?

 

[Falcon_LS]

Originally Posted By: gomes512
What was happening and may still be happening is that the grime is creating "hotspots" in the system.

I've had good luck with the commercial cleaning kits on units that we're gummed from Dexcool.


Thanks!

Originally Posted By: chevrofreak
Run a lower temperature thermostat. I have a 180 in my 96 crown vic and it runs great, and the detonation is quite a lot less than it used to be. I also replaced my MAF sensor because the barometric pressure reading was lower than it should have been for my elevation, which contributed to the detonation.


I've tried running a Motorcraft RT-1144 thermostat (180 F), and it hasn't really done much. I've noticed a delay reaching operating temperature, but that was it. How did you check the pressure reading?

Originally Posted By: mechtech2
If the gas octane is up to what the car specs, then a problem could be running too hot, or advanced ignition timing.
An EGR system could be faulty.

I am hesitant to run a cooler thermostat, but a 185 could help.


Any particular component of the EGR system, DPFE perhaps?

Originally Posted By: Scott_Tucker
Have you tried running premium fuel?


When I dump 98 RON/93AKI in there, there is no pinging. But fuel economy takes a dump. With 95 RON/91 AKI, there is no difference compared to 91 RON/87 AKI.

 

[eljefino]

I saw what you're seeing back on my 92 ciera 3300. Only running pure water cured it; believe it was a localized hotspot. BIL's Century with the same motor ran perfect.

Keep up the good fight of cleaning things out. Consider maybe your water pump is not 100% up to snuff? Maybe moving enough coolant to not overheat and to work the thermostat right, but not enough to get some isolated corner down to the right temp.

 

[Shannow]

Good point re pump.

When I was mucking around with inlet thermostats, the pressed steel impeller pumps pumped nothing at idle. The cast impellers pumped at all revs

 

[Falcon_LS]

Never thought of a weak pump - thanks! I'll replace that this week, considering it's literally a 10 minute job and about $70 for a Motorcraft one.

How long did you run pure water for by the way?

There's no pinging before the engine reaches operating temperature, no matter what. As soon as its up to temperature, that's when it starts.

 

[chevrofreak]

Originally Posted By: Falcon_LS
I've tried running a Motorcraft RT-1144 thermostat (180 F), and it hasn't really done much. I've noticed a delay reaching operating temperature, but that was it. How did you check the pressure reading?


I have a Scangauge II, and I programmed in the gauge for barometric pressure.

 

[Falcon_LS]

Originally Posted By: chevrofreak
I have a Scangauge II, and I programmed in the gauge for barometric pressure.


Thanks! I have an OBD-II reader I run off my laptop, called ScanXL with Ford Enhanced Diagnostics. I haven't really had much time to play around with it, but I'll see if it has any similar functions.

Having said that, I got a new coolant pump and before I install it, I'm going to flush out the system. I will take my time with it, so I drain, flush, refill and let distilled water circulate for a while before repeating. Then I'm going to fill up with just distilled water, take out the thermostat and add Motorcraft VC-9 Engine Cooling System Iron Cleaner. I'm going to take it for a one hour drive on the highway, then come back and thoroughly flush out the system again, reinstall the thermosat and refill 2 gallons of Motorcraft G-05 and 2 gallons of distilled water.

 

[motorguy222]

Have you checked the radiators fins?

The radiator could be bad,not leaking but not able to cool as it once did.

You can check the fins by gently running your thumb nail over the fins,if they are easy to push over or seem to crumble,that could be your problem.

When the fins do this,they cant remove the heat from the radiator like they are supposed to,that makes the car run hotter.

 

[mechtech2]

You are concentrating on the cooling system.
Sure, it could be faulty, but it is only one of many things to consider.

 

[chevrofreak]

Originally Posted By: mechtech2
You are concentrating on the cooling system.
Sure, it could be faulty, but it is only one of many things to consider.


True, especially since our older Crown Vics have no knock sensor. I've been chasing a detonation issue in my 96 for years.

I've used dozens of bottles of fuel system cleaner, I've used water decarbonization, I've switched to colder spark plugs, I've replaced the MAF, I've run Red Line Water Wetter, and I've changed the thermostat. The thermostat did the most good, but mainly because it was making the engine run too cool. The computer requires the coolant to be somewhere between 180 and 190 degrees before it will update the barometric pressure. Mine had been stuck at 26.1 since I installed the new MAF, and my water temperature never got above 181F. I had a suspicion that my engine wasn't getting hot enough for it to update, so I installed a 195F thermostat today. The barometric pressure reading is constantly being updated now, and it is much lower than the 26.1 that it previously had been (now between 25.5 and 24.8, which is normal for my elevation). As a consequence, my detonation is back to what it was before the colder thermostat swap. I am getting better fuel mileage, though.

I'm done chasing this problem. I get 89 octane for the same price as 87, and it almost completely cures the detonation. I'm just going to be using that from now on.