Anir

Allen,

Fuel injector and valve deposit cleansers such as Techron and Lubro Moly are very useful maintenance products, IMHO. I believe Techron itself is officially endorsed by several high-end manufacturers, such as BMW. Chevron adds a small amount of Techron ("naphthene"?) to its premium unleaded pump gasoline.

I have used these additives for several years in various cars with uniformly favorable results. My Infiniti dealership in Atlanta routinely used a similar product called BG 44K to clean fuel injectors on customers' cars.

Perhaps, you're thinking of engine oil additives such as Prolong, which purport to coat the cylinder walls with friction-reducing Teflon and the like. To my knowledge, these are unproven and even potentially harmful products.

Sanjay Prasad

I heard about this problem the other day from a dealer while looking at a '95 993. I was told that the problem is only in 96-98. Apparently, the '95 model did not have some sort of recirculation at cold start that seems to cause the problem. I was a bit suspicious as the dealer was trying to sell me a '95 and I mentioned that I had seen a '96 elsewhere, but judging from this thread the problem is real.

I was wondering if I should go for a '95 because of this problem, but judging from the messages on this thread, the fix (techron and italian tuneup) looks pretty easy, and fun! Any specific reason to favor a '96 over a '95, other than age/mileage? Thanks in advance.

Sanjay

Rick in Portland

Viken,

I believe Steve recommends changing the oil after a heavy treatment of Techron because a small amount of Techron will get past the rings and contaminate the oil.

Steve?

Steve Weiner-Rennsport Systems

Hi VB:

The oil was changed for two reasons, this flushes the material that was dissolved by the treatment that dilutes the oil; it finds its way past the rings.
The other reason is that fresh oil helps facilitate passing emission tests.

A 4-gas or 5-gas tester will show that the engine runs the cleanest with fresh oil in the crankcase.

Ran

Sanjay,
I have not heard of this happening much at all. While the facts may well be true, there appear to be easier solutions as pointed out by Anir and Steve. In any event, you should probably look at the overall picture as regards the different model years - there are pluses and minuses with all model years and even the much maligned 99 model yr 996s are not all bad. Just an opinion that this carbon build-up issue should not outweigh many others. I am not going to point out some of the 95 model issues in this thread so as to keep this carbon build up thread on topic. Perhaps you would like a new thread to discuss the pros and cons of model yrs.
Best of luck in your hunt for your 993. It is fun. I hope you get to test many cars since that is the best way to figure out what you like and what you want to live with.

Ran

Steve,
Am late to this cleanup party and Techron insights. Would appreciate it if you would fill me in on how much Techron to add on that last fill up before going for oil change. Or, if it is more appropriate the ratio for mixing with last fill up... Or will we just follow directions on bottle - have never bought it so I dont know if it comes with directions. Also, I did not see any "Techron" but saw two types of "Pro-Guard" with Techron by Chevron (one was labeled for Gas treatment and the second one was "Progard with Techron for fuel injector PLUS intake valve cleaner")
Thanks in advance for your help.

amfp

I use the 12 ounce Techron prior to oil changes which is about every 3-4K miles. The bottle instructions state 1 oz for each gallon of gas, but because I change the oil so often, I only use the 12 oz. BTW, 20 oz should also be fine.

I add when the fuel tank is about 1/4 empty, then fill tank with fuel. Techron works best in city type traffic as opposed to straight highway travel as it works more extensively through the system. I keep the tank of fuel with Techron until about the 1/4 level and then fill the tank. Then probably within 500-1,000 miles change the oil.

Most auto supply store carry Techron. Here's a URL for more info.
http://www.chevron.com/prodserv/fuel...ch%5Fgas.shtml

STLPCA

And here's a source for LubroMoly Ventil Sauber and Jectron mentioned in the thread.


Olympic Imported Parts - LubroMoly Additives

911MSN

I had this clean up done at my local dealer recently (3 month ago). It was said to be 4K job but Porsche had paied for it :-) One of service guy told me that they get this work done time to time. I use my car for my commute (17 miles one way) and i have about 52k miles on my car.

Pete in DC

Just informed my 96 C4 (avec check engine light) has 'blockage in the secondary air passages.' I had Techron'd when the light came on and before I brought her in, so will continue to monitor, then try MotorVac (or this BG Induction thing?), then.... <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />

cmoss

It's for real. I purchased a '96 (62K miles) and ~2K miles later... Noisy valves and a dignosis of carbon build-up in the "secondary air circulation system."

Prescription: New e-valve guides, machine head, clean/clean/clean.

Cost: I've heard anything from $6k to $10k.

There was at least one other there undergoing the same procedure. I've also heard pretty much what others have said...

Lots of running around town at low rpm's (&lt;3K), very bad.

Techron... Very good. But you have to use it regularily.

Note: The dealer I took the car to performed a "dye" test that is designed (I think) to help detect valve wear. The service rep said it was much better than a leakdown and/or compression test.

Any way, just got it back... I'll watch the low revs (I had them install the LWF ), and use Techron...

Hope this helps,
Chris

bigbpainta

Hi,

This is interesting! Also very much concerns me as I thought these cars were bullet proof. I own a 96 993 which runs fine aside from a rough idle. I have had no check engine light come on and the car has plenty of power through the whole power band. I am curious, do you think using thechron will smoothen out the rough idle? Do your cars run perfetly smooth or do they have a kind of cam idle?

Matt Vaughan

BigB, just take your car out to a track and drive your car how it's meant to be driven. These cars ARE bulletproof -- obvious when you get it out on a track and run it like there's no tomorrow. They'll take it and ask for more! The harder you drive them, the better they run too.

c4-toy

Ditto... on the air injection passages cloging up. Happened to my 96 C4, 55k miles, engine light came on. Porsche dealership ate the cost of the repair (aprox $900), but only after i did a complete tune-up ($1400 includig new wire's and connector's). I have heard this is VERY common, more than people think. Usually the left bank of the engine. This was also confirmed by an email i sent to Bruce Anderson, and he explained it well.

RT7

I only use Chevron super-premium w/Techron gas. Would this help?