Need quick help with advice on a purchase of a 4000SQ
tigran at tigran.com
Tue Jan 27 03:52:34 EST 2004
I doubt many here remember me but about 15 months I was bugging this list
with fuel tuning problems with my '85 4000CSQ. After much headache, blood,
expense and torture I finally gave up on the car's Satan-possessed fuel
distributor and went back to working on my 3000GT VR4.
Well, the VR4 snapped a piston rod bearing while I was racing (and
shamelessly beating) a turbo'ed Honda S2000. I won the race and made $500,
but unfortunately my can limped home with loud knocking of a lose rod
bouncing around on the crank. Given as it is my 3rd engine swap in a year on
that car, I think I am done with it for a while. (For the record, the
original engine got 24 bent valves from a piece of gasket going into the
timing. The $10K replacement sport all-forged engine I built tore itself to
bits in less than 1000 miles because the shop that built it did not install
the thrust bearings correctly causing crank walk an metal debris clogging up
everything touched by the oil - even my brand new $2200 15G turbos...)
Anyhow, I am in car hell.
In the meantime, while looking online for a cheap daily driver I came across
an '85 4000SQ. It is missing a few things compared to my CSQ, but the
interior/exterior in it is the best shape of any Audi of that vintage that I
have ever seen. Overall the car is VERY clean and almost mint. The owner
seems clueless about the car and was telling me about some tranny problems,
which I did not feel at all after driving the car. The car does have 220K on
it, but he wants under $750 for it, which to me sounds like a deal having in
mind that the dealer wanted $600 for just a used fuel distributor a year
ago. Here are the problems I need help with.
First, he tells me that he replaced the timing belt on his own. He seems
like an honest nice guy, but he did not come across to me as a mechanic. In
fact asking a few simple questions about timing (which I have done 5 times
on my 3000GT) all I got was blank stares. His garage also didnt have a wide
veriety of tools which I would think would be required for the job.
Second, the car is heating up REALLY fast. Less than a minute after starting
it I saw the temp gauge start to climb, which did not happen for 5+ minutes
on my other 4000CSQ. Driving it around a .5mi loop the water temp needle
went up past the half way point. I drove it about 1/4mi down a hill and then
got on it a bit going back up - the needle got past the 3/4 point on the
gauge. The reason I was looking so closely at the needle was because he told
me that he just recently (within a week) replaced the water pump because the
old one just started gushing water one day. I feared that the car may have
been run with no water pressure and overheated causing the block to warp.
When I got back I parked the car and let it run a while fully expecting the
temperature to keep climbing as I have seen with other warped engines. To my
surprise it actually gradually went down to normal over the course of about
5 minutes. I verified that the fan worked as I heard it kick in and out but
the thing that sounded strange was that even with the water temp way up
there (after the hill climb) I heard it turn off and then turn back on a few
minutes later. I would expect with a temp like that for the fan to stay on
until the car cooled down...
Third, with the car running, I do hear a little tick coming, then getting
quieter, then louder again. I NEVER had any ticking with my other (197K mi)
#1 Is the 4000SQ (5Cyl 10V) motor an interference engine? Meaning, if the
timing belt snaps or skips, will the pistons hit the valves? Assuming the
timing belt is lose or pops off, am I looking at getting a valve job?
#2 What can cause this overheating and how can I test for it without digging
into the car? I'm thinking maybe clogged radiator or bad thermostat... Is
there any tell-tale sign of engine warpage with this car? I did check the
radiator fluid and it was filled (way overfilled too) with brand new fluid.
#3 Are the water temp gauge and the radiator fan relay ran by the same
sensor? If not, could one of them be malfunctioning and causing the gauge
read too high or the fan to not stay on long enough? With my other 4000CSQ
the problem was opposite, I had trouble getting the temp up there until I
read about the sensor getting too cold because of oncoming air from the
front. I built a little cardboard shield around the sensor and the problem
#4 Does the 5Cyl 10V motor have hydraulic lifters? If so, the ticking I
heard may be lifters...
#5 Any other advice or things to check for are welcome. I am a pretty good
wrench-hand and have torn my old Audi to pieces, so I sort-of know where
stuff is on this car...
Main thing I want is an easily driveable runabout car. I dont mind doing
radiator work or something of the sort but I REALLY dont want another car
that needs the engine pulled anytime soon.
Technical Manager, Uptime Technical Solutions LLC.
tyson at up-times.com
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