Cooling Problems - caused by wrong intake?

[CapnCrunch53]

Hey guys, I'm at my wit's end here, I'll try to keep it brief. Basically while attempting to replace my thermostat on my 5.7 TBI, my friend broke the t-stat housing bolts, ended up mangling the threads in the intake, and eventually swapped in another intake manifold he got from a machine shop.

Ever since then, I've been having cooling issues, even after having the coolant flushed and filled by the shop. Takes forever to warm up, then when it does it gets to the red. Haven't been able to drive it for weeks. First instinct is the new t-stat is bad.

I was not there (had class) when my friend picked up and installed the replacement intake. The guy he bought it from said it's from a 96-97, which would make it from a Vortec... he also said it used a different style thermostat, and looking at parts for different years from O'Reilly's, it looks like the Vortecs did use a different t-stat design, so I think it really is off a Vortec.

Here's the question: Should a vortec intake manifold on a TBI engine with TBI heads work? Getting conflicted answers on google... but my gut feeling says no. About ready to strangle my friend...

 

[volunteerff21]

Vortec motors use an entirely different intake design and fuel injection system than a TBI motor.

TBI's have a traditional one piece intake with your throttle body mounted on top. (Just like a carb set-up)

Vortec's have a lower aluminum intake with a plastic upper plenum. The fuel injectors are stuffed under the plastic plenum.

In short.....no, stock Vortec intake will not work with TBI heads/motor. It won't even bolt in place.

 

[CapnCrunch53]

Ok, that's what I was afraid of. So I need to go find myself an intake from a TBI motor. All this because of a thermostat! Grr...

EDIT: Wait just saw your edit. It won't even bolt in place? then maybe I do have a TBI intake after all... so maybe I do just have a bad thermostat.

 

[volunteerff21]

Any markings on casting numbers on the intake??

 

[volunteerff21]

Ok, that's what I was afraid of. So I need to go find myself an intake from a TBI motor. All this because of a thermostat! Grr...

EDIT: Wait just saw your edit. It won't even bolt in place? then maybe I do have a TBI intake after all... so maybe I do just have a bad thermostat.

Correct. Mounting holes are entirely different. Could just be a bad thermostat.

I'm not 100% sure what other intakes will bolt onto those TBI heads. If it's not a factory intake it could be an aftermarket Edelbrock or something similar. But like I said I'm not 100% sure.

 

[CapnCrunch53]

I'll check when I get home from class. What's confusing me is if its a TBI intake (and it does run so it must be right?), why did my buddy tell me it uses a different t-stat design? He said he tried the original t-stat and it wouldn't physically fit... Thanks for helping me figure this out, I don't know jack about this stuff. I'll check for casting numbers when I get home.

EDIT: That's a possibility I hadn't thought of. An aftermarket TBI intake, maybe one that used the later style thermostat? It's a thought anyways...

 

[volunteerff21]

I'll check when I get home from class. What's confusing me is if its a TBI intake (and it does run so it must be right?), why did my buddy tell me it uses a different t-stat design? He said he tried the original t-stat and it wouldn't physically fit... Thanks for helping me figure this out, I don't know jack about this stuff. I'll check for casting numbers when I get home.

EDIT: That's a possibility I hadn't thought of. An aftermarket TBI intake, maybe one that used the later style thermostat? It's a thought anyways...

As far as I know the thermostat design stayed the same on the factory intakes throughout all the TBI years (If I'm wrong there someone please chime in).

For aftermarket ones I have no idea

 

[CapnCrunch53]

Yeah that's whats confusing me. Anyways I looked at it and found no markings other than the firing order and cylinder numbering. I think the best thing to do is gonna be take the thermostat out and just take it with me to O'Reilly's and see what it matches with. Seems like it's probably the new t-stat getting stuck partway open, which would explain taking longer to warm up (when it should be closed), and getting too hot (when it should be fully open). Good to know I'm not gonna need another intake manifold though, thank god. Thank you for your help!

 

[Horns]

Take some pictures of the intake. That would help us help you tremendously.

~Via Mobile

 

[jdyates]

What horns said. I have an aftermarket Vortec intake with my TBI (long story, long build), but the thermostat housing are still the same as my old TBI TStat and housing. It sounds like a bad TStat, maybe they broke something or forced it in during installation. Or maybe even installed it upside down? Not sure if thats possible but its another start. Another possibility is your coolant temp sender going dead. Like $14 and a quick swap. When it heats up do any warning lights light up on the dash? My coolant gauge goes to the red at operating temp (no ground wire on the cyl. Head) and the "check gauges" light comes on.