Alright, I recently installed LPP clone headers and finally got all the fitment issues worked out. Upon driving it home tonight, after a while it started getting hotter than usual and finally climbed enough to concern me. I found that if I was in neutral it would at least hold steady at whatever temp it was at and if I was rolling in neutral it would slowly come back down. Now, it seems like it an issue with the transmission maybe getting hot and bringing up the radiator temp, thus overheating the whole car. But wait, there's more :-p:

I had to replace the gauge temp sender, the oil pressure sender as I broke them during header install. I had to eliminate the oil cooler and re-route the coolant lines together, which shouldn't have changed anything coolant wise as the way I did it, all that happened was instead of flowing through an oil cooler it goes right from the water pump to the radiator like it did before but without the oil cooler is all. This bumped my oil pressure to like 70psi though upon starting it and it stays at like 60 when in gear at anything over 1800 rpms. I noticed this when I was kicking it it in neutral on my way home trying to keep the temp down. When it was kicked in neutral it would drop to like 45-50 psi where it normally rode before. However, this could be off as it is a new oil pressure sender and it could be off some...as at idle at low rpms it shows the pressure I used to have at higher rpms before. But it could also be because the oil cooler is gone...I have seen posts about this being the case sometimes.

Anyway, sorry for the novel here, but I am just trying to get all the info. out there. It is not the cooling fans as they are running...checked and saw/heard them running when I popped the hood when I finally got it home. Any ideas on this would be appreciated.

Also, I will be getting something to verify that the temp. is in fact getting that hot and will double check the coolant level again when the car cools down some to make sure it is none of those things. But so far it seems to be right on and I bled the cooling system already and checked it a few times over the past few days before finally driving it home as it has been at the shop for a while now. Thanks in advance.

 

Odds are you just haven't fully bled the system after rerouting the coolant line. Did you have the bleeder screws open when you were filling up the radiator? I'd wait until your car is fully cooled down. Then I would open the radiator and fill it up with the bleeder screws open, closing them when you see water come out. Start the car, top off the radiator with the car running. Cap the radiator and let it get to full operating temp, ~210-230* with stock fan programing. Then shut it off and let it cool down completely and restart the process until when you open up the radiator after the car is stone cold and you see that the radiator is still completely full.

 

I did that cycle at least once so far...bleeders and all, but I will definitely be doing it again. A lot changed and a lot of coolant was drained so I'm sure there was plenty of air to be bled out. I hope that is all it is. Would it be worth while for me to run the heater while bleeding at operating temp as well you think? Could I have gotten air in the heater core?

Either way, I will be doing the complete bleed cycle again for sure. I was just wondering if there was some other reason it could be doing this...header/"y" pipe running by tranny causing it to run hotter...oil cooler being gone making it run hotter...maybe a combination of both. Like I said, there are a lot of variables as I changed more than just the headers. just trying to cover my bases here. Don't want to overheat her :-)

 

Yes, run the heater on max heat.
Headers shouldn't affect your temps.

 

I was just thinking it could be a totally unrelated issue with maybe the tranny...just coincidentally started after installing the headers. Or maybe the things I changed or the oil cooler might have done something...that was my only concern really. I will bleed it all again and see where I am at.

 

Alright...update:

I just rechecked that everything was bled and checked cold level and it was. I will double check again tomorrow morning when it is coldest to make sure as I ran the heat some tonight as well...still overheating. Ran up to between the 220 and 260? mark...just before the line right below red line.

I did however notice something on the dyno and think I may have felt it finally as well when driving it just now. It kept kicking in and out of torque converter lock-up on the dyno we think as the run was sporadic in the beginning until the later rpms of both runs. And it felt as though it was kicking in and out of gear or lock-up driving it slowly down the road just now...like it was hunting a bit/slipping maybe? If the tranny is slipping I imagine the temps would climb dramatically which could be some of it I suppose. Any support for this theory? The fluid doesn't really smell burned though and looks good. I will check again in better light tomorrow of course, but I suppose it could be just starting to do it. It has been rebuilt once in it's life already at about 60K I believe the previous owner said and it now has 118K give or take as the speedo is off from the 3.73 gears. It could be time again I guess for a rebuild but I got 90K out of my '94 T/A trans and have heard of many more making it the distance too. I don't beat on it bad, but who knows what the previous owner did.

Anyway, this is the latest in the '93 T/A saga. Any thoughts?

 

More food for thought:

I also have an electric water pump, the throttle body bypass...which used to just have 2 bolts blocking off the lines that when I installed the headers I ran a union to them and let it flow through, and the oil cooler when removed shortened the coolant lines and I unioned them too more toward the radiator/water pump as well. This in mind, could the lack of resistance in these now flowing coolant lines be my problem? Any chance the water isn't going through the radiator now or flowing too fast or something and causing it to overheat now. It's really the only variables related to the cooling system since the header install and the system is bled.

 

Unioning the two coolant lines was a good thing. That allows the steam pipe to connect to the radiator, which helps equalize pressure and helps prevents air pockets.

Are you sure both fans are still working?

 

One was for sure...I will have to check the other one tonight after I get home from work as the car is at home now. That's my next check. I'm also bringing home an external temp. gauge to verify the temp is actually what the gauge is reading and not just reading high and well within normal running temps or something as I did replace the temp. sender for the gauge.

 

yeah dont you love those stock gm gauges

my favorite is the fuel tank gauge haha

 

It's not the gauge, it's the shape of the tank causing the float on the fuel pump sending unit.

 

Alright, latest update. System is bled for sure now. Fans are coming on. Temp gauge for CPU must work as the fans come on at the right time based on the external gauge I have. The problem is in the gauge/sender/wire somewhere. It reads about 30-35 degrees higher on the gauge than it actually is. Would more resistance in the wire cause a higher temp reading or lower? The sender itself reads about the same as the engine temp. based on the laser temp gauge which I thought might have been the problem with the headers...but it is reading basically the same temp on the outside of the sender as the engine actually is, so I don't think it is radiant heat fouling up the reading.

Basically, would more resistance in the wire cause a higher reading or lower on the gauge?

 

No dice on resistance figures? I looked at the wire to the sender and it appears to be ok, but I did break the original sender when installing the headers and had to replace it during the process. Any chance the replacement sender is off just a little like that...i.e. 40*? The plug matched up and it was a 2 prong, looked just like the original...but was Carquest, not the dealer...so...