The Stupid Engine Questions Thread

[SUBURBAN5]

Catalytic converter

 

[PlayingWithTBI]

331 PPM HC (220 allowed)

High HCs usually mean it's running rich or misfiring. As @SUBURBAN5 said, cat can be the issue too. I'd try a tuneup 1st. Pull the plugs and look at them for fouling or other issues.

 

[Jehu]

High HCs usually mean it's running rich or misfiring. As @SUBURBAN5 said, cat can be the issue too. I'd try a tuneup 1st. Pull the plugs and look at them for fouling or other issues.

Thanks for the suggestions. I'll start with plugs and air filter.

 

[Godholio]

95 K2500 burb, 7.4/4L80E, big radiator. Driver's side hard lines are AT cooler, passenger's side are engine oil, right? Any known-good or known-bad brands? I went through a hell of a time with my JK Wrangler and awful 3rd party radiators before giving up and buying autozone.

The upper driver's side fitting, just below the upper hose, is goobered up with cracked JB Weld and is seeping coolant but I don't think I'll be able to disconnect the fitting without breaking something. Thanks, previous owner.

 

[SUBURBAN5]

95 K2500 burb, 7.4/4L80E, big radiator. Driver's side hard lines are AT cooler, passenger's side are engine oil, right? Any known-good or known-bad brands? I went through a hell of a time with my JK Wrangler and awful 3rd party radiators before giving up and buying autozone.

The upper driver's side fitting, just below the upper hose, is goobered up with cracked JB Weld and is seeping coolant but I don't think I'll be able to disconnect the fitting without breaking something. Thanks, previous owner.

Mine a 98 c1500 and there opposite. driver engine oil passenger trans with also aux cooler. I recommend ac delco. But I dont have a 2500 lol. I actually would upgrade to yours when mine done for because you should have a wider core then me

 

[Godholio]

Yeah, it's about 40" wide overall, core is about 34" wide. The lines on the driver's side are much thicker than the other side's, so I figured the thicker ones were ATF.

Delco's list price is $650, seems to actually sell for a bit over 400. Still overpriced.

 

[SUBURBAN5]

Are you looking at rock auto. Also remember I have a 1500. I would think 2500 the same but it very well could be different. Also o'Reilly's had a good radiator. I liked there warranty but the one over here was being dumb with me when I wanted to claim the radiator as a warranty. So I ended up getting ac delco on Amazon.

 

[Godholio]

I always consider rockauto. My default choice is the Spectra, though I also can't tell which filler neck I have. Mine measures just over 1" taller than the top of the side tank, but in the pictures the raised neck seems 2-3" tall and the lower neck looks almost flush.
I'd prefer an all-aluminum, but I had two Mishimotos fail from shoddy construction in my Jeep, and they're the only 3rd party brand making AL radiators for these trucks that I'm familiar with. Spectra's been good quality in my experience, even though I'd rather not have plastic.

 

[alpinecrick]

Picking up a 98 K1500 (350) today. It has this nasty coolant that looks like it was Dexcool in another life and I want to swap it for the regular green.

They sell these back flush kits where you connect a water hose to a tee at the heater hose inlet, run the engine and watch it empty through the radiator cap opening all over the place.

Questions:

1. Is this sufficient to clear all the old coolant out so I’m not mixing new green with old Dexcool?
2. Would the thermostat be left in place or gutted out? Seems like it would have to be gutted or removed and a gasket found.
3. To get all the tap water out, would you suggest pulling the knock sensor and other drain plug on the block?

1) Yes.
2) I leave mine in, if I recall correctly the instructions don't say anything about removing the thermostat.
3) Removing the knock sensor is sufficient.

Most likely sometime in it's life DexCool and conventional coolant have been mixed--I suspect this has happened a LOT to GMT400's because the DexCool thing was relatively new and a lot of people didn't know better.

Mixing Dexcool and conventional coolant is bad ju-ju, and you are a very smart dude to flush the system!

Immediately change the fuel filter and the trans fluid while you're at it!.......

 

[SUBURBAN5]

I always consider rockauto. My default choice is the Spectra, though I also can't tell which filler neck I have. Mine measures just over 1" taller than the top of the side tank, but in the pictures the raised neck seems 2-3" tall and the lower neck looks almost flush.
I'd prefer an all-aluminum, but I had two Mishimotos fail from shoddy construction in my Jeep, and they're the only 3rd party brand making radiators for these trucks that I'm familiar with. Spectra's been good quality in my experience, even though I'd rather not have plastic.

I hear you. I agree I dont care for the plastic either. But that's why i look at warranty because i know it will not last forever. Lol. Cant help you with the neck. I would think it's the tall because of the additional coolant tank but if the both got the nipples for the hose idk lol