Installed Custom X Pipe Exhaust and Now Engine Overheats

[JoesEdge]

Hey guys! I'm a little stumped on this one. It could be a total coincidence, but let me explain what's going on.

So on Monday I had a custom X Pipe exhaust installed using my Jeg's 2 champer knock-offs on the Duster. The exhaust is dumped before the axle. It's pretty loud at idle, but sounds great when cruising.

I don't know if it's at all related, but now my engine overheats. Is that even possible that an exhaust upgrade could even affect engine temperature?

Before the dial would barely get past the second line, and now it goes like 3/4 of the way. When the temp gauge is at 3/4 and I drive it steady at about 40 to 50 MPH, it cools off a bit to half. I did this at night.

I'm running a 26" Aluminum 2 row radiator and a viscous fan clutch with fan.

My guess is that the X-Pipe is so efficient at scavenging that now I'm running so lean it's causing the engine to run hot.

Or....maybe my temp sender or temp gauge is faulty. Maybe the thermostat is faulty. Heck, I don't even know if I have a thermostat actually.

What do you think?

 

[Phreakish]

Sounds like further diagnosis necessary. Without independent verification of the engine temperature, it could be any of the sender/gauge issues you raised.

Without knowing what else you may have touched while installing it, or where the welding leads were attached, it's tough to say if something else might be up.

Without o2 measurements, it's tough to say if it's gone lean. This could even be confirmed if you had ir temperature measurements off the exhaust before/after. If you were leaning out from the X pipe alone, you'd likely feel an unquestionable difference in the performance.

 

[JoesEdge]

Sounds like further diagnosis necessary. Without independent verification of the engine temperature, it could be any of the sender/gauge issues you raised.

Without knowing what else you may have touched while installing it, or where the welding leads were attached, it's tough to say if something else might be up.

Without o2 measurements, it's tough to say if it's gone lean. This could even be confirmed if you had ir temperature measurements off the exhaust before/after. If you were leaning out from the X pipe alone, you'd likely feel an unquestionable difference in the performance.

Just wanted to note, that I installed the custom X-Pipe due to my crappy installation job of the Jeg's A-Body exhaust kit (driver's side pipe was hitting the body, and the tail pipes were hitting the leaf springs) and for better performance.

Funny that you mention O2 measurements. I don't know what they were before, but I'll know soon enough what they are current. My new AEM A/F gauge should be delivered today. That should at least tell me if I'm running lean. I do need to weld in the bung and wire it up.

Performance wise, even though the guage is telling me it's hot. It drives GREAT. It's a manual trans car, so transition from a dead stop to cruise speed is good. Acceleration is good too.

I guess I was hoping for some confirmation that these two events are no way related and it was just a coincidence.

You did mention the welding leads. My guess is that it could have blown out some circuitry somewhere? Maybe blown out the factory temp gauge? Is that where you're going with that? I do have spare I can test.

 

[RustyRatRod]

Did you disconnect the battery before welding?

 

[JoesEdge]

Did you disconnect the battery before welding?

The shop where I took it did the welding so I can't say for certain whether or not they disconnected the battery.

It's a reputable exhaust shop (the only shop in town that can do mandrel bends) and they've worked on my cars before with excellent results, but oversights can happen.

 

[Phreakish]

You did mention the welding leads. My guess is that it could have blown out some circuitry somewhere? Maybe blown out the factory temp gauge? Is that where you're going with that? I do have spare I can test.

It's possible it had an effect, even if it didn't fry anything.

 

[vntned]

Years ago, I had an '84 Omni GLH that I converted to a GLH-T. When I put the engine, the only exhaust I had was the open 2.5" down pipe. I had an entire mandrel bent stainless 2.5" exhaust kit for it, but my muffler guy was about an hour and a half away. As soon as I got on the road it started running hot. So I kept stopping, checking the water level, constantly watching the gauges. Get to my buddy's shop, he installs and welds up the exhaust system for me, and it NEVER overheated again! Not even close, always ran super cold after that!

So long story short, Turbo Omnis are better with a full exhaust!

 

[JoesEdge]

Years ago, I had an '84 Omni GLH that I converted to a GLH-T. When I put the engine, the only exhaust I had was the open 2.5" down pipe. I had an entire mandrel bent stainless 2.5" exhaust kit for it, but my muffler guy was about an hour and a half away. As soon as I got on the road it started running hot. So I kept stopping, checking the water level, constantly watching the gauges. Get to my buddy's shop, he installs and welds up the exhaust system for me, and it NEVER overheated again! Not even close, always ran super cold after that!

So long story short, Turbo Omnis are better with a full exhaust!

Wow...so it could be possible it had an effect.

Yesterday, my son played around with swapping carbs from Holley to Edelbrock AVS, then he put the Holley back on and fiddled with it some more.

I took the Duster out last night, and it drove OK (I think I still need to fiddle with the carb because it wasn't' 100% right) and didn't overheat. The temperature stayed in the middle most the time. Drove it around town in circles trying to see if it would get hot. I even drove it on the freeway for about a mile. It would pretty much stay in the middle, go a little past, then go down just before the middle, then back to the middle again. It did that cycle. BUT...it was a cool evening (finally after it being hot and muggy) so maybe that had something to do with it.

Now to keep things on topic to exhaust, the exhaust sounds great. Looks great too. I should take some pictures and video. It's quieter while driving that's for sure. The sound at idle has mellowed out since the first day it was installed.

The shop I took it to is called Gene's Mufflers in Downey, CA. The do great work actually.

Here's a quick video.