GeneralDisorder

It means "Cover Your A$$", and that's exactly why they put that stuff in the manual. The "conditioner" (stop leak) was left in the manuals after the gasket re-design in case some percentage of the new gaskets also had this problem. In practice they don't - 100% of the '03+ redesigned gaskets leak OIL ONLY. Thus the bottle of fancy mudslide is completely superfluous on anything but a 99 to 02 model with original gaskets (which there are basically none of left in the wild at this point). So if it makes you feel better to use it - it's unlikely to cause any short term damage. But it's also not solving anything and may cause long-term issues if used excessively. I wouldn't. It's pointless on that model. GD

The manual is a CYA. 03+ don't leak coolant. Period. The "conditioner" is a stop leak product - it's actually re-branded Holt's Radweld from the UK. It's full of solids to clog up small leak paths. It's basically fancy dirt. Pour some out and see for yourself. You don't need it. GD

Get quotes from multiple dealers and get them bidding against each other. Ask to speak with the internet sales manager - usually corporate and internet sales are non-commission. GD

Yeah that will get ya every time. Glad I could help. GD

Forgot to plug in coolant temp sensor. Pull codes. GD

2005 models don't leak coolant and don't require the conditioner additive. That was 99 to 02 models. 2005's leak oil only. Conditioner is not needed and will only make the system dirty. GD

I posted at the same time as you - didn't see your reply. It wasn't a correction. Either term is fine really. But the line is used for the VR to sense the voltage output at the "main junction" - which, in practice, is not actually the main junction, it's just a ways down from the BAT terminal - I really have no explanation for why this was done other than to save money on wire because they really didn't care to do it the right way.... If you want to get into semantics though a "signal" is generally going to be something generated externally.... GD

Head gaskets. Always. The external leak affects all 2.5's from 1999 to 2010. They will leak as early as 30-50k and usually get really bad around 70-90k. The better the maintenance, the worse and faster they leak. GD

S is for Sense, and L is for Lamp. It's a standard GM remote sense internal regulator. In practice this means the S goes to about a 12 AWG wire that merges back into the BAT lead about 10" down the harness. The L is a +12v that runs through a dash lamp and then to the alternator. It's the battery indicator on the cluster and is also the field flash that starts up the alternator. GD

Its not an expansion tank. It's the upper reservoir. It keeps the level of coolant higher than the turbocharger. The overflow bottle IS the expansion tank. Same thing. Its going somewhere. If you smell it its on the outside of the engine. Put the pressure to it. GD

You need to disassemble the IAC and clean it. Happens all the time with these. Replace the plugs and wires with NGK (both). Appearances mean nothing. This is a normal tune up maintenance item. Just replace them or you may be chasing your tail. GD

On a turbo you have to do it at the upper water tank. GD

The heater core is solid aluminium - tanks and core. The radiator will go before the heater core goes. GD

The turbo model was made in 83 and 84. If its an 85 body it was swapped. They DID NOT make EA81 turbos in 85. Got that? Dont modify it. Parts are virtually impossible to find. If you kill it, that will be the end of it. Love it for what it is. GD

No less than 6k or its just wasting money. That Amsoil is good for 15k in gasoline applications using the Amsoil filter. GD

Also you can buy the plugs for the 95 to 99 - it's the same plug thats used on the 86 to 94 Nissan Maxima alt. And the swap is simple - big wire to big wire, little wire to little wire. The older EJ alt with the +12v lead only uses this for the internal VR.... I ALWAYS swap those alts out on the first gen legacy for the 95 to 99 unit and cut that silly yellow lead. They have more amps and they are crazy cheap from the dealer for high quality. GD

Just open up the trans and swap in the 23 spline stubs. The rest is easy. GD

The turbo itself is basically incapable of burning coolant. The cooling passages are cast into the iron CHRA housing and are not open to any of the shaft bushings, or mechanical seals. The huge plumes of smoke you see from turbo failures are straight unburned oil dumping into the turbine housing and being sucked into the compressor housing and into the cylinders. GD

No question that the sensors are good. They almost never fail. And have been swapped, etc. Now - assuming your other tests are all correct and you havent missed anything (power and ground to ECU whole cranking) then I have no choice but to assume the cam and crank signals cannot be understood by the ECU, or are not present. What needs determining is if the signals are getting to the ECU and are in alignment with one another, not missing any triggers, sufficient amplitude, and signal integrity. Do not take for granted that the valve timing is correct. I have seen the marks all line up and it still be out of time more than once. Remember the pulleys have the marks on them - the shafts are not gauranteed to line up with those pulleys unless the keys are intact. Something you only find out upon tear down. GD

Turbo models don't exhibit the HG problems of external weepage. If you can smell it, then it's a leak that can be fixed. Run the pressure up to 25 or 30 psi. You'll find the weakest link. What aree you afraid of? If anything fails at less than 2x nominal system pressure it should be replaced anyway. GD

87 to 89 RX Turbo 5 speed.

Use the 95 to 99 alternator. It doesn't have the yellow +12v wire. Dealer has reman for like $85

Not difficult if you know anything about compressed air systems.

You need scope traces of the cam and crank sensors.

It's just 4 12mm bolts. Two for the lower and two for the upper section. The upper section bolts are straight back between the cusions. LS, LSI, and turbo models had fold down pass through seats. L models did not. Wouldn't help you anyway. Still have to remove the whole unit.