General Questions

[Spidey]

I picked up a 1996 Grand Prix SE in January. It's got 144,000 miles and zero rust. I was happy to find it because it was mechanic-owned by an older gentleman. I was especially excited to find that it already had the intake gaskets and head gasket replaced and the heads were ground. The car was also gone through, MAF sensor, TPS, all the filters and fluids, and other sensors. It couldn't run any better. I had a '94 Grand Prix SE a couple years ago and it the the opposite in terms of maintenance. But both cars have the issue with holding air in the cooling system and erratic cooling and heating. I still have my yellow radiator funnel from my last car--the best tool you can have for a 3100. But, now to my questions:

 

My car leaks a good amount of antifreeze. I have to put in about a gallon every two weeks. I can't see any external leaks, but it is winter, so they'd be hard to see. There isn't any antifreeze in the oil, and it's not going through the engine because it runs just fine. The hoses are good, and it has a new water pump and radiator cap. Where is the antifreeze going?

 

The engines clicks when it is cold. It lasts for about 3 minutes before it goes away. I've read all over about this, and a lot of people say the 3100 pistons were designed to fit loosely to reduce friction on the cylinder walls. And after they heat up, the pistons expands and the clicking goes away. I question this theory, because my Oldsmobile Ciera with the 3100 with similar mileage makes absolutely no clicking at any temperature. Should I be concerned with this noise?

 

I'm also curious about performance. I'm pretty aware of some of the more typical pedestrian mods, but I wanted to see some 3100-specific opinions. I know that a K&N cone filter won't to anything for my naturally aspired engine. I've read that you can actually lose power from them. And I know that a cat-back exhaust isn't going to help me at all, either. I've read that the best gains come from a new throttle body, either one from a 3400 or a bored out one. I've also read about the benefits of installing a new down-pipe. I don't know if getting a bored-out intake manifold will help me at all, but I've seen those for sale, too. My question is, what relatively easy modifications will safely give me a few more ponies at the wheels.

 

I am also an audio technician. I plan on doing a relatively extensive audio overhaul to this car. I am a big fan of the door speaker location these cars have. Everything is stock right now, and I plan on thoroughly documenting a high-end installation to help people get the most out of these cars in terms of sound quality.

 

I appreciate anyone who has read this far. Thanks in advance for your expertise.

[rich_e777]

Not many mods for a 3100. Some guys have top swapped with a 3400 and that does a little. The downpipe coupled with a cat back will do a little + a high flow cat. Headers have been discussed but issues with the bend on the rear have come up. Ignition system is already a good one and AC delco plugs work just fine. E3 diamonds seam like to much of a gimick but I could be wrong. If airflow is increased in the LIM is always a plus and a larger throttle body will give you a quicker response time. A true CAI will do some as well but it needs to be getting true cold air and not just a cone and shiny pipe.

 

If you want some real power a L67 swap(3800 w/ Supercharger) with a 4T65 trans is a somewhat popular way to go. Eventually i will be doing this mod which is why i havent done anything to my `94. Probably going to hire someone whos done it before to lead that project. I dont have any audio upgrades either ATM and will be real interested in what you come up with, been wanting a system that is MP3 user friendly and has some considerable sound without adding a huge box in the trunk.

 

Alot of other guys have done all kinds of things as far as performance and im sure they`ll be along to add to it or correct me if I got something wrong.

[Schurkey]

My car leaks a good amount of antifreeze. I have to put in about a gallon every two weeks. I can't see any external leaks, but it is winter, so they'd be hard to see. There isn't any antifreeze in the oil, and it's not going through the engine because it runs just fine. The hoses are good, and it has a new water pump and radiator cap. Where is the antifreeze going?

Pressure-test the cooling system. Sometimes helps to park on top of a clean sheet of cardboard, or to at least verify that there's no anti-freeze on the pavement before you begin the test. Be sure to check the carpet on the passenger side for coolant; a defective heater core may fill the front-seat footwells. I would pull all the plugs, pressurize the system, look for obvious leaks. Then LEAVE THE PRESSURE ON FOR AT LEAST AN HOUR, overnight would be better--but perhaps it doesn't hold pressure that long. Crank the engine and see if you have a geyser out of one or more spark plug holes.

 

A gallon in two weeks, no external signs of leaks? First Guess: Head gaskets or intake gaskets. Your spark plug on the affected cylinder(s) will look like new--no deposits because the entire combustion chamber will be "steam-cleaned".

 

If you find wet cylinder(s), you'll be due for a new O2 sensor, and perhaps a catalytic converter.

[Spidey]

This is the only site I've found to have anything for the 3100 at all:

 

http://www.milzymotorsports.com/

 

From my research, I've seen that the only noticeable performance upgrades came from a downpipe/high flow cat, and a throttle body. MMS has both parts, so I'm pretty interested. I've definitely come across the L67 swap, and while it sounds delightful, it's just not something I would do. I'm looking for a more bolt-on path to performance.

 

I've got some leftover equipment I'm going to use from my W202 project. It's all top-end stuff, so I will be installing it right. I plan on putting a good 4 weekends at least into my system. I've got a CDA-117, 5.25 Focal K2 Power, and a 4 channel SoundStream Reference amp, which I plan on by-amping the Focals with. I've also got a 10" JL W3 V3 in a custom sealed box--I put about 2 weekends into that box alone. It should be quite the system. Like I said, I plan on extensive documentation to help people out.

[19Cutlass94]

http://www.WOT-Tech.com

[rich_e777]

www.WOT-Tech.com

[Spidey]

This is the best site I've seen. Has anybody ever tried modding those Grand Am headers for a Grand Prix 3.1? I would imaging it would be next to impossible to do, but I really have no idea. If I were to get both stage 2 intakes and a 56mm throttle body, would I see a difference? Would it be comparable to an LG8? Thanks again for all the help here.

[19Cutlass94]

Your would have to heavily modify the rear header. Your almost better off dropping in a complete 3400/(large port)3100. You won't see much of a difference with just those intakes and a TB. The head ports on your motor are so small it's like a bottle neck with those large port manifolds on there.

 

 

Sent from my iPhone in some random spot of Texas.

[Spidey]

When you say a 3400, are you referring to the DOHC or the OHV engine? How difficult is a complete swap like this? Would I need a new transmission? What's the typical cost of a swap like this? I know that the DOHC is pretty quick, faster than a stock L36.