Fluid recommendations

[louis_white]

Hi all, I’m replacing all my fluids on my 1990 c4 so looking for recommendations please on the best to use.

engine oil?
Coolant?
trans?
Brake?
power steering?

Any others I’ve missed

thanks

 

[Redlevel]

In my '87, I use..

Engine..
Mobil 1 10w60 Full Synthetic (older car/high mileage from Opie Oils). Changed every 10k miles or two years. We don't live in Alaska so we don't need the very cold spec, one type does all, type engine oil. Check the attached chart. Full Synth is best as it retains its body unlike that mineral stuff which turns to runny black ink after a few thousand miles. My old oil goes in my mates '71 MGB as its still good! Leave the "Classic" or "Duckhams" oil to the Morris Minor guys!

Coolant..
Bluecol or BlueStar or Halfords 2 year.

Trans..
MPM Dexron 111F/G (discounted usually 50% at Eurocarparts).

Brakes..
Dot 4 or 5.1. (do not use Dot 5 as it is for silicon systems).

Power Steering..
I been using Lucasoil Power Steering Stop leak/conditioner 100% (topped up with regular ATF for over 12 years now). Get an oil syringe and suck out all the old oil and replace. The Lucasoil product is slightly thicker and gives great feel to the steering. Steering oil should be replaced every couple of years or so to keep the system healthy.

Diff..
Mobil Synthetic diff oil for LSD's (I forget which one) plus 2x bottles of GM's diff additive.. Did mine two years ago and it cost me £90 all in ffs!!

 

[Redlevel]

Talking of brakes, get under the drivers sill and check your brake bundle. There are 4x brake pipes with a 5th one in the middle of the bundle which is the evap pipe from the tank to the charcoal can in the front nearside corner.
The evap works like this..
Petrol vapour pressure builds up in the tank and it gets evacuated down the pipe all the way to the charcoal can where a solenoid opens a valve and the petrol vapour is sucked into the throttle body to be burned. This is a US environmental thing, not required in the UK and means your fuel cap is non-vented.

Problems?
The evap pipe runs over the axle on the nearside and gets corroded and blocks up, resulting in a 'whooosh', letting out the pressure when you open the petrol cap.
What I did?
When I replaced my brake pipes with Kunifer pipe (copper/nickel alloy), I removed all of the evap pipe and the charcoal can and associated valves, vacuum pipe and solenoid and plugged up the port at the throttle body. Sounds complex but if you take a good look, it isnt really.
At the tank end, I replaced the pipe with a simple "roll over" valve so that it shuts off in case I'm inverted. This valve allows the tank to breathe normally when I'm the right way up...
Check the straps along under the sill where the brake pipe bundle is supported as this is where the corrosion starts.
If yours are ok, clean them up with a soft wire brush and paint on some rust remover product. Then coat later with something like Waxoyl (I use Bilt Hamber products for dealing and preventing rust).
The only other places rust might be a problem is the petrol pipes (offside sill) and the autobox coolant pipes to the radiator or oil cooler if you have one.
The steel petrol pipes come from the tank, over the axle and down along the sill. Check this area of the petrol pipes for corrosion as they are exposed here. Again, if they are ok, clean and paint them.
The autobox coolant pipes also corrode so the same treatment here.
This is important as you cannot reach the autobox fittings (I'm contemplating cutting a hole in the trans tunnel near the passenger seat to access these pipe fittings from inside!), so dropping the box to replace the steel pipes (my current problem! ) is one way of accessing these fittings, but I have an angle grinder and I'm not afraid to use it!!
The alternative is to cut back these steel pipes and fit 5/16th (7mm) Gates hydraulic autobox replacement cooling hose which I could not find in the UK and had to buy a 25' length from Rockauto (only need about 10'!)
So, if your autobox pipes are good, clean, derust and paint as soon as you can.
It helps if you have mate with a ramp or lift, I dont, and have to wrestle under my Corvette with drive on ramps!
Good luck!

 

[louis_white]

In my '87, I use..

Engine.. Mobil 1 10w60 Full Synthetic (older car/high mileage) (Opie Oils). Changed every 10k miles or two years. We don't live in Alaska so we don't need very cold spec, one type does all, type engine oil. Check the attached chart. Full Synth is best as it retains its body unlike that mineral stuff which turns to runny black ink after a few thousand miles. My old oil goes in my mates '71 MGB as its still good! Leave the "Classic" or "Duckhams" oil to the Morris Minor guys!
Coolant.. Bluecol or BlueStar or Halfords 2 year.
Trans.. MPM Dexron 111F/G (discounted usually 50% at Eurocarparts).
Brakes.. Dot 4 or 5.1. (do not use Dot 5 as it is for silicon systems).
Power Steering.. I been using Lucasoil Power Steering Stop leak/conditioner 100% (topped up with regular ATF for over 12 years now). Get an oil syringe and suck out all the old oil and replace. The Lucasoil product is slightly thicker and gives great feel to the steering. Steering oil should be replaced every couple of years or so to keep the system healthy.
Diff.. Mobil Synthetic diff oil for LSD's (I forget which one) plus 2x bottles of GM's diff additive.. Did mine two years ago and it cost me £90 all in ffs!!
View attachment 8530

Thanks for this bud, your a star. I’ve ordered oil and Blue ACDelco long life coolant now. I will order the other fluids that you recommend now

 

[louis_white]

Talking of brakes, get under the drivers sill and check your brake bundle. There is 4x brake pipes with a 5th one in the middle of the bundle which is the evap pipe from the tank to the charcoal can in the front nearside corner.
The evap works like this..
Petrol vapour pressure builds up in the tank and it gets evacuated down the pipe all the way to the charcoal can where a solenoid opens a valve and the petrol vapour is sucked into the throttle body to be burned. This is a US environmental thing, not required in the UK and means your fuel cap is non-vented.

Problems?
The evap pipe runs over the axle on the nearside and gets corroded and blocks up, resulting in a 'whooosh', letting out the pressure when you open the petrol cap.
What I did?
When I replaced my brake pipes with Kunifer pipe (copper/nickel alloy), I removed all of the evap pipe and the charcoal can and associated valves, vacuum pipe and solenoid and plugged up the port at the throttle body. Sounds complex but if you take a good look, it isnt really.
At the tank end, I replaced the pipe with a simple "roll over" valve so that it shuts off in case I'm inverted. This valve allows the tank to breathe normally.
Check the straps along under the sill where the brake pipe bundle is supported as this is where the corrosion starts.
If yours are ok, clean them up with a soft wire brush and paint on some rust remover product. Then coat later with something like Waxoyl (I use Bilt Hamber products for dealing and preventing rust).
The only other places rust might be a problem is the petrol pipes (offside sill) and the autobox coolant pipes to the radiator or oil cooler if you have one.
The steel petrol pipes come from the tank, over the axle and down along the sill. Check this area of the petrol pipes for corrosion as they are exposed here. Again, if they are ok, clean and paint them.
The autobox coolant pipes also corrode so the same treatment here.
This is important as you cannot reach the autobox fittings (I'm contemplating cutting a hole in the trans tunnel near the passenger seat to access these pipe fittings from inside!), so dropping the box to replace the steel pipes (my current problem! ) is one way of accessing these fittings, but I have an angle grinder and I'm not afraid to use it!!
The alternative is to cut back these steel pipes and fit 5/16th (7mm) Gates hydraulic autobox replacement cooling hose which I could not find in the UK and had to buy a 25' length from Rockauto (only need about 10'!)
So, if your autobox pipes are good, clean, derust and paint as soon as you can.
It helps if you have mate with a ramp or lift, I dont, and have to wrestle under my Corvette with drive on ramps!
Good luck!

I need to purchase some drive way ramps, so I can get under the old girl but I will definitely check all these when I can get to them to look. Really appreciate the info, sounds Berry technical but like you say once I’m under there and looking I’m sure it will all become clear and I can get cracking on it. Thanks buddy

 

[Redlevel]

Thanks for this bud, your a star. I’ve ordered oil and Blue ACDelco long life coolant now. I will order the other fluids that you recommend now

Long life is usually 5 year and not always suitable for older cars. Bluecol and BlueStar are an actual brand..
Make sure you flush out thoroughly, maybe a few times as some coolants dont mix and the Yanks use green Dexcool which may turn to mayonnaise when mixed with another UK type.

Dexcool had a few warranty problems with new cars in the US.

DEX-COOL specifically has caused controversy. Litigation has linked it with intake manifold gasket failures in General Motors' (GM's) 3.1L and 3.4L engines, and with other failures in 3.8L and 4.3L engines. One of the anti-corrosion components presented as sodium or potassium 2-ethylhexanoate and ethylhexanoic acid is incompatible with nylon 6,6 and silicone rubber, and is a known plasticizer. Class action lawsuits were registered in several states of the US, and in Canada,[20] to address some of these claims. The first of these to reach a decision was in Missouri, where a settlement was announced early in December 2007.[21] Late in March 2008, GM agreed to compensate complainants in the remaining 49 states.[22] GM (Motors Liquidation Company) filed for bankruptcy in 2009, which tied up the outstanding claims until a court determines who gets paid.[23]

Flush it out, as just when you think you got it all, you're wrong and need to do it once more.
Speedflush helps and Ive heard a crushed dishwasher tab does a good job although I never used it myself, ..yet!
You need an IAT (inorganic additive technology)

What is Antifreeze? What is Engine Coolant? | Opie Oils

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[Redlevel]

I need to purchase some drive way ramps, so I can get under the old girl but I will definitely check all these when I can get to them to look. Really appreciate the info, sounds Berry technical but like you say once I’m under there and looking I’m sure it will all become clear and I can get cracking on it. Thanks buddy

Dont overthink it.. Corvettes arent so complex. They are just assembled by Dan and Bubba in Kentucky, ..not by faceless technical pogues in white coats in Stuttgart!
Use Youtube to advise and help like we all do..

 

[Redlevel]

The cooling system of an L98, runs around 220deg as standard. This is really hot and reliant upon the radiator fan (fans, if you have the Z51 or Z52 handling packages, check with the label in the console lid..) working, as if it fails, the temp reaches 260+deg in a heartbeat and will defeat the expansion bottle billowing glycol like a WW2 fighter with a radiator hit..
This happened to me and I no longer have the bottle for these high temps so now I run a new fan with a separate, non standard, adjustable temp control and a 160deg thermostat with 3x 3mm holes bored in the flange to let air bleed through.
Normal hot running for me is around 180-190deg..
Save this for another day and just focus on getting yours running well..
p.s. Check between the front of your radiator and the aircon intercooler for a build up of litter, leaves and other crap which will impede airflow..

 

[louis_white]

The cooling system of an L98, runs around 220deg as standard. This is really hot and reliant upon the radiator fan (fans, if you have the Z51 or Z52 handling packages, check with the label in the console lid..) working, as if it fails, the temp reaches 260+deg in a heartbeat and will defeat the expansion bottle billowing glycol like a WW2 fighter with a radiator hit..
This happened to me and I no longer have the bottle for these high temps so now I run a new fan with a separate, non standard, adjustable temp control and a 160deg thermostat with 3x 3mm holes bored in the flange to let air bleed through.
Normal hot running for me is around 180-190deg..
Save this for another day and just focus on getting yours running well..
p.s. Check between the front of your radiator and the aircon intercooler for a build up of litter, leaves and other crap which will impede airflow..

So glad I have access to memebers like your selfs with all this knowledge. It’s really going to help me with my build. Appreciate it

 

[Rich]

So glad I have access to memebers like your selfs with all this knowledge. It’s really going to help me with my build. Appreciate it

Lewis - that's the reason this Club exists and we have many, many great contirbutors on the website.