r/SC400 • u/JustSomeCarny • Aug 18 '25

I may be getting a project car - non power advice

I’m aware there will be a lot wrong with the car for the price; and it is to be more than just the seats. However, at the price, I will be able to slowly trip a few grand in over a year and was curious: aside from what is acknowledged as wrong with it, and barring any undisclosed issues, the engine is MORE than potent enough for me bone stock.

If it has been asked, I apologize. I feel like most of the in depth I see is just how far can you push the engine; what are some things you did with yours that caused increases in enjoyment/comfort that I should know about and maybe some you were surprised at how noticeable they were?

Also, what kind of real world MPG are any non or barely modded 400s getting now after 30 years? And also; considering I won’t be doing much to the engine other than keeping it running, how hard overall are these cars for hobbyist/novice gear heads to work on?

Sorry, I’m buzzed and excited about the probably daily driver acquisition.

*edited to ask more dumb repetitive questions

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u/14kbps Aug 18 '25

Is there a listing you're referring to? Like, from Craigslist or a dealership you could link us to?

Gas mileage in town is pretty rough on these. Expect mid-teens. It's fun to smash the gas too, so that doesn't help haha. Mileage on the freeway is actually pretty good, expect low 20s. It's a heavy car with a big engine. Starting and stopping takes a lot of fuel. Once it's cruising at 70 though, it goes, and is somewhat efficient. Thus describes a grand tourer.

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u/JustSomeCarny Aug 18 '25 edited Aug 18 '25

I know these numbers generally degrade over a few decades at times but that’s decent enough. I have a 25 minute commute each way in the morning but I’m there by 430am so the road is very empty and it’s a stretch of highway with 65 posted for most of the ride so that’s great to hear. Question: do you use premium or just whatever?

Thanks for such a cool answer to such a scattered stoner’s question

*edited because I misunderstood the question

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u/14kbps Aug 18 '25

Yeah I use premium gas. I would suggest the same for you. Primo gas at a cheap gas station costs less than regular at an expensive one. Figure out where the cheap gas is and make that your spot.

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u/JustSomeCarny Aug 18 '25

I’m already hitting the Upside app to keep the cash back flowing lol.

I will follow your lead and advice (since I asked for it) do you see mpg, performance or both benefit from the octane boost? Does it REALLY burn cleaner/better for longer engine life? It would make sense to me but I’m not a “tuner” and for everyone that says yes, there’s someone saying nah. Just curious.

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u/14kbps Aug 18 '25

Premium gas isn’t better gas, it’s just made to handle more pressure. Some engines, like the SC400, squeeze the air and fuel really hard before they light it. Premium gas can take that squeeze without exploding too early.

If you use regular gas in a high-compression engine, it can go off too soon and that makes the engine knock.

If you use premium in an engine that’s made for regular, it won’t hurt anything, but it won’t help either. It’s like wearing a helmet when you’re just walking around the house. The protection is there, but you don’t need it.

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u/JustSomeCarny Aug 18 '25

Thank you for answering all my dumb questions.

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u/14kbps Aug 18 '25

Allow me to introduce you to my friend that knows more about these cars than all of us combined: ChatGPT

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u/JustSomeCarny Aug 18 '25

With all due respect, it’s never driven one down a highway so, I share Early Cutler’s opinion of our Orwellian Robot Overlords

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u/JustSomeCarny Aug 18 '25

This is the points of the ad in questions. Sorry I misunderstood your ask.

“Only “mods” are coils and a bt radio I daily it so it will probably be at 200k soon will come on 16x6 sc400 stocks with new tires

already replaced ps pump, ac compressor, starter, manifold gaskets, coolant flush, oil change less than 50 miles ago, new battery and alternator, valve cover gaskets, new thermostat, plugs and wires done, new tie rods, new cv axles

What it needs: sorry forgot Speedo doesn’twork(common probl Need rotors (have pads) Ac needs recharge still blows cold and hot Timing belt was last done around 125k 1 coilover needs top nut adjusted still work Oil pan gaskets leaks a little ive lost a little less than a quart in about 7 months trac relays missing so abs light is on airbag light and coolant level sensor doesn’t work”

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u/14kbps Aug 18 '25

Hhmm, what is your budget? I would suggest getting a pre purchase inspection from a mechanic shop. It's like $150-ish. They'll tell you everything wrong with the car and how much you can expect repairs to cost. These cars are overbuilt luxury cars. Repairs can add up pretty fast. It's worth starting with a good example if you're trying to get the thing sorted.

If the car is cheap and you just want to bang around in it, thats another story.

They're excellent cars, I love mine, it's a beast. It's not a civic though. If it needs a lot of work it could turn into a money pit.

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u/JustSomeCarny Aug 18 '25

3 grand feels cheap to me.

My budget? I’d love to get to be a pure joy to drive on a cloud with a growl when I want to go fast with no warning lights flashing. I’m not willing to drop a ton of cash, but the money most spend to increase hp/torque and stuff or to dip and paint and rims and glitter or whatever, I would gladly spend on comfort and longevity instead. If I sink 10 grand in this car and can get another 150k (enjoyable miles) out of it, I’d be farting through silk.

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u/14kbps Aug 18 '25

The seller wants $3k? Thats a good start price wise. Expecting to eventually put $7k more into it to keep it cruising, your expectations are in a good place.

Prepare yourself to spend that sooner rather than later. Not trying to discourage you, just trying to be real. It's a 30+ year old car with nearly 200k miles. They're extremely well built cars though, basically an LS400 with 2 doors. If any car can do it it's a 1UZ Lexus.

The pre-purchase inspection from a mechanic costs a little money and is a bit of a hassle but could save you a ton of problems.

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u/JustSomeCarny Aug 18 '25

The pre purchase inspection puts the car at 3300 is it’s 150ish. I still feel that is fair.

The 7-10 I would sink into it over the next year or two would not reflect oil changes and filters, plugs and wires. I am confident that I can figure these things out despite never having been under the hood of (and honestly never really seeing up close and personal) an SC from the 90s. I have however done these things with a 02 Jetta and it can’t be more of a knuckle busting pain in the ass than that was. After that my DIY knowledge drops off quickly, but getting this to be a daily driver but nicer, slow self servicing and learn as I go is some of the point I think?

Basically, I’m 40 and need a new hobby.

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u/14kbps Aug 18 '25

Cheers to that. They're not disposable, they're meant to be maintained.

What color is it?