Any help or advice will be greatly appreciated!!

[Big L]

I have a 2001 Deville DHS with 78,000 miles. Drained and re-filled coolant system and the car was never the same again. Shortly after (few days to 1-2 weeks at the most), the check coolant level DIC kept coming up, but the level was fine. The car then had a sudden loss of power and ran as if it were low on coolant, and fuel economy suffered as well. When I mean loss of power I'm talking 4 bangers are literally hurting my feelings!!

I purchased a new coolant tank to replace the sensor and purchased a new thermostat, drained and refilled, but no performance increase. The DIC message is off and there is enough fluid, but it still sounds "low".

During this time the power steering pressure line developed a leak and needed to be repaired too. I was able to replace the power steering hose, but now there is a hissing noise that is very audible while at a standstill. I found that if turning the steering wheel ever so slightly the sound goes away.

I bought new delco plugs, but found what looked to be corrosion in a few boots on the first 2 coils so I quit. I want to replace all boots, but as of now no one has stock. Also, there is a small amount of oil in the spark plug cylinder, I rented a block tester from autozone and it did not detect any carbon.

Also - Recently replaced the fuel filter and I've only used shell's highest grade gas since I got the car 4 years ago at 37,000 miles. The throttle body was pretty bad, so I cleaned that and I also cleaned the MAF.

Any clues!!!??

[JimD]

Originally Posted by Big L

Any clues!!!??

You mentioned a DIC message and a few symptoms but not a single Diagnostic Trouble Code (DTC). You and we need the DTCs to proceed with any kind of systematic diagnosis.

Here is how to display the DTCs on your model;
http://www.cadillacforums.com/forums...-sevilles.html (How To Pull Codes On '98-'04 Sevilles and '00-'05 Devilles)

[Ranger]

Have you pulled the DTC's? Checked the fuel pressure? Checked the FPR? Checked for a plugged CAT?

Turn the wheel from lock to lock 10 or 20 times to bleed air out of the system.

[Big L]

Oh, sorry. No codes. I checked through the DIC, my scan tool and my elm327 usb scan tool. All are coming up with nothing.

[Big L]

I had midas check the cat and they said it was good. My fuel pressure was around 36 lbs until I replaced the filter now it is at 40-41 (within norm), all this according to Midas. What is a FPR? Thanks for the quick responses.

[Ranger]

FPR = Fuel Pressure Regulator. See the Tech Tips section. Very easy to check.

[DevilleDeeman]

Man, don't take your Cadi. to Midas..they are crooks!

[Big L]

Originally Posted by DevilleDeeman

Man, don't take your Cadi. to Midas..they are crooks!

I'm learning that now. $917 later they still had no idea. They only checked the cat and fuel filter/pressure when I asked what the results were? And, they actually tried to charge me $63 for a fuel filter!!

Ranger: Thanks for the advice on the steering. Noise went away after following this procedure (Midas replaced the pressure hose - I even tried to explain that sound was new and they gave me a dumb stare).

I've checked a few times for Tech Tips, even did a search (yielding different posts), is there something I'm missing? Could you provide a link? I know it's probably right under my nose, but I'm missing it.

Thanks

[Ranger]

Go back to the Tech Tips forum and start with the last page and work you way forward. I think it is way back there (very early post).

[submariner409]

A bit of oil in the plug wells is common: the wells are sealed by O-rings in the cam cover and they tend to weep. Not a problem: petroleum oil is a non-conductor (if it were, your submerged 12VDC fuel pump would be a real bomb...........).

FPR - in the right rear of the fuel rail, held in by a hairpin clip. If fuel comes out the (disconnected) vacuum nipple, replace it. Use a dab of oil on that lower O-ring. (Make sure the old one comes out. www.rockauto.com)

[Big L]

I will check the FPR tonite/tomorrow morning. While searching online for the best way to clean the spark plug boots, I found this link http://en.allexperts.com/q/Auto-Part...-corrosion.htm. Will this work? Is this a smart way to clean my engine compartment? I will be replacing the boots soon, but the dealer has to order them. I want to swap plugs this weekend, but don't them to sit in that corrosion, and the bay could use another cleaning.

[Ranger]

Sounds a little extreme to me.

[submariner409]

Plug boots - www.rockauto.com, your car, ignition, spark plug wires/boots. Packs of 4. Or www.gmpartsdirect.com

DO NOT pressure wash or try magic cleaner potions in or around a Northstar. WD-40 is good for some things, but it forms a film - don't get carried away.

You may be surprised to find some white snot ("corrosion") in the new plug boots. That's dielectric ignition grease, used to seal the plug insulator from moisture and arcing.

[Big L]

Originally Posted by submariner409

Plug boots - www.rockauto.com, your car, ignition, spark plug wires/boots. Packs of 4. Or www.gmpartsdirect.com

DO NOT pressure wash or try magic cleaner potions in or around a Northstar. WD-40 is good for some things, but it forms a film - don't get carried away.

You may be surprised to find some white snot ("corrosion") in the new plug boots. That's dielectric ignition grease, used to seal the plug insulator from moisture and arcing.

I checked the site, but they are out of stock. My dealer says they can get them in 2 days, but they are closed on the weekend. I figure I can get them next week.

[Big L]

I just checked the regulator and it is good. No signs of fuel.