While you are there (major service)

I would change out some seals at the front of the engine. I have a few oil leaks from the front of my engine, but I'm due for my engine out. Basically I wouldn't want to have to go back in after a year to replace the front crank seal if it decides to let go. Maybe check some of your metal oil lines and things like that, one of mine is a bit crushed. Clutch and diff can be done in the car at a later date I believe.



Sent from my GM1917 using Tapatalk

 

A long list could be generated…. But my fav is the cheapest: the check valve on your exhaust. Two at about 15usd ea.

 

Doing a diff with the engine in is a bad idea.



Since October 1985 when Testarossas arrived at US dealers I have not changed a single front seal. Most leak as a result of damage from installation when someone replaced them.

Shift shaft seals do leak from time to time but are not any harder to change in the car. If you are doing a differential it is a little easier then.

 

Not sure if that is a total list or an additional list. The belts kind of confuse the issue.
I feel about the same on the rear seal as the front. Those we do see leak sometimes however not as big a risk as it is easy to get to.

Cam seals are pretty normal as are the O rings. Valve adjustment and head retorque.

Some replace seals in the waterpump every time. To me that kind of depends on how long and how far since last service. I also know a lot of people had a bad time installing them and not have a leak at the end of the job. The updated one piece seal is to me the only one to use but that is the one some had problems with.

Someone else said exhaust check valves. I agree but not on the price. Years ago I had a couple of the cheap brand X valves go bad and melted, burned up everything up stream of them. Since then I have only used genuine GM/Delco valves and have not seen them for $15 each in some time. Maybe he has a better source. In any event it is not a huge difference.

On the hoses, most important are the fuel return. Replace both and most of the time I replace the 4 small vertical hoses from the tanks to the fuel vapor pipe and the air outlet hoses from the tanks to the filler pipe. Fuel pump supply hoses and fuel tank connector hose should be inspected. Be very careful removing hoses from the aluminum nipples. They break easily.

Also thats just to plan on. Your real job is to inspect everything.

 

I am in the midst of a major as I write this. The engine in my car ran perfectly when I started, so as mentioned, the process seems to be inspect and replace old parts before issues arise.

This time, in addition to new belts, a clutch (it did not slip, but I am in there anyways), a billet differential case and new LSD clutch disks, I will replace the 30 year old chain and tensioner which operates the oil and water pumps. My rear main seal was leaky and made a mess, while the clutch throw out bearing seals were also in need of replacement (sometimes the clutch would stick in the in position momentarily when I released it). I am also replacing the bearings and seals which are on either side of the differential and all ball bearings and seals in each rear wheel hub.

Things I replaced last engine out 5 years ago included both thermostats (hard to reach with the engine in) and the rubber hoses which drain oil from the cam boxes to the sump (they become petrified over time and leak no matter how tight the hose clamps were). I suspect I will replace the thermostats again this time.

When you replace fuel lines, as mentioned by Rifledriver, do not forget the fuel tank vent hoses on the rear firewall (after 30 years mine crumbled in my hands and were a major fire hazard).

If your brake caliper flex hoses are original, consider replacing them when it is easy to do so. Same goes for old rubber coolant hoses and radiator fans (old ones seem to draw a lot of current which risks your fuse box).

My shift shaft seal always leaked until I swapped from the original o ring seal to one which had a proper seal with a lip. Amazingly, my car does not leak oil anymore.

Finally, if the car is that far apart, consider switching to non-water based coolant like Evans. I run it in all my old cars and have only good things to say about it.

 

Can you please add some details on the seal?

“My shift shaft seal always leaked until I swapped from the original o ring seal to one which had a proper seal with a lip. Amazingly, my car does not leak oil anymore.”

 

The shaft usually rides in a rubber o ring located inside the transmission case. I replaced that (it still leaked) so I then added the gearshift shaft oil seal that Superformance sells (146306) in addition to the o ring (the seal taps into the hole in the case from the outside). The combination of both seals (and a proper fitting bellows to keep dirt out) has finally stopped the drip.

 

As the difficult to reach bearing and carrier wears over time, is not well lubricated and is not extremely expensive (compared to the clutch itself) I intend to replace both parts. My car operates in a harsh desert climate, has 60,000 km on it and has original parts, so it's time. I will probably go with the original OEM clutch over the AP type as I have had zero issues with it.

 

My shift shaft seal always leaked until I swapped from the original o ring seal to one which had a proper seal with a lip

I 3D printed an adapter to add the 512 lipped seal to my 1985 dated gearbox. Fixed my problem as well.

Excellent list of updates, well built!