Purchasing and Ownership Advice
Buying advice on G50 Q45 (90-96)
Congratulations! You are looking at one of the finest cars ever created. However, they are not without plenty of shortcomings. Here are some major stats and facts about the 1st generation Q45. A lot of my own personal opinion and experience is interjected, so if you don’t agree, sorry you didn’t take the time to write this article!
Variations of the Q45:
Q45a: Designation for the Q45 with active suspension
Q45t: Touring model, minor differences except for upgraded wheels, and a rear sway bar.
Difference between the 90-93, 94-96; and problems associated with them
The first generation Q45 is said to be the best of a PERFORMANCE-LUXURY sedan, where performance is first and luxury is second. The 90-93 is said to be the purest of these. Real leather door panels, vinyl covered dash, some of the best plastics in the industry, and not a hint of bling-bling wood trim or anything like that. Everything was built for a purpose: No grille because it creates wind resistance, no wood trim because its worthless, and so on. There are many features that are only in the best of cars today. I dare you to find EVERY interior feature in 20 mins in the first time you sit in a G50 Q. The car also came stock to start in 2nd gear, to have really smooth starts, and then when you drop it to 1st, it unlocks the fury of the VH45. They used plastic where they shouldn’t have, and that’s the timing guides. Unfortunately it’s a well researched and known ordeal, but not always known by many old Q owners.
A description of the timing chain guide issue
Defect: On the slack side of the timing chain system, they used plastic backed timing chain guides. What happens is they eventually crack, break, and this causes the chain to flop around, and it can and eventually will jump a few teeth. The VH is an interference engine, and most of the time it completely destroys the engine. However, this is only prevalent in mostly higher mileage engines. Most failure are around the 120k range, and some have gone higher. A friend of mine and fellow Q owner, Jesda, has a 92 Q45, that has 185,000 miles on his Q. Just recently, he had his guides replaced. Here is some pictures of his ordeal: http://q45.spilky.com/iowa/ . He and the previous owners were VERY OCD about changing the oil (mobil 1 synthetic), and that is what I feel that saved his engine. As you can see on the pictures, he was on borrowed time. ALL 90-93 Q OWNERS, IF YOU THINK “THIS WONT HAPPEN TO ME” YOU ARE WRONG BECAUSE EVERY Q OF THIS ERA WILL FAIL AT SOME POINT IN TIME. It is very unfortunate to see these engines go to waste, because they have only broken in by the time most have failed.
Fix: Metal backed guides were introduced. You switch the old guides out. If the guide pieces are missing, you MUST drop the oil pan and remove the old guide bits, because it will clog the oil pickup and possibly starve the engine for oil. On an interesting note, by the time you’ve done 2 timing belt changes on a early Lexus LS400 you have already paid for the guide job on the Q, and you only have to do it once!
Other common issues: Please see our TECH HELP section for more information
Everything is applicable except for the following changes:
Basically all off the same issues EXCEPT the guides are there, except not really as bad. Injectors were restyled and are more reliable, but they still fail, especially in areas with iffy gas, California and Arizona being the worse. In most peoples opinion, these are overall the best Q45s to get because of the better reliability and lower cost to own, and more luxury. However its not by any stretch of the imagination gone drastic changes, its still very much a drivers car.
The 96 model year got OBDII (on-board diagnostics) and lost variable valve timing as a shortcut to meeting emissions standards, thus much closer to advertised horsepower and torque (actual power output is higher than advertised).
What to look for when buying a 90-96 Q45.
First thing is to visually inspect the exterior. Look for variations in the paint (there should be little orange peel, if any). If there is, its probably been repainted at some point. There’s only one common rust area on the Q, and that is on the rear, where the plastic bumper meets the rear quarter panel. Its uncommon to see a Q with exterior rust, and if there is run away, because it probably hasn’t been maintained well. However its just that small spot I wouldn’t worry too much.
Just make sure everything works. Don’t worry about any STOP LAMP INOPERATIVE messages or something similar to that because they can all be fixed easily. Be concerned if it does say TRANSMISSION MALFUNCTION.
Something Ive noticed on many Q is the little interior lights go out. I have many out in my Q right now. They go behind many switches and there are tons of them. Another thing like that is the rear ash trays, most flop around and are broken.
There are many things with the Q engine that can be easily inspected. A look inside the oil filler cap is worth 1000 words. You need to really look down in there with a flashlight as far down as you can see, and you should only see cleanness. If its black or really dark brown stay away.
Check the engine oil. The level should be good, and the oil a nice golden color if its been recently changed. When you wipe it off, in the little round part of the stick, there should be no goo there.
Other fluids: Brake fluid (should be clear; slightly yellow); transmission fluid (red, and should NOT be brown or smell burnt); powersteering fluid (same as tranny fluid).
With the engine running at idle, you should feel no vibrations, it should run about 650rpm fully warmed (just below the line between 500 and 1000). If its below this then the intake will need cleaning, and do NOT ADJUST THE IDLE SPEED, it needs to be corrected by cleanliness. You shouldn’t really hear much, you will here some slight ticking of the injectors opening. Its very soft and anything else should be taken note of. The fan should show resistance when moved (engine off).
On the lift
Check for body damage, rust, and other damage. Also check the suspension components, namely the rubber bushings for leaking of silicone or cracking. They are used with age and not with miles.