Serious Engine Issue - '90 Coupe

[Guest rojelio77]

Fellow Reatta Enthusiasts - Sadly I have encountered what appears to be a serious engine issue with my '90 coupe. I was cruising down the freeway at a modest 30 mph, heard a clunk / pop and the car died. The temp was fine, oil plentiful, but oil pressue was kind of low. This car usually operates with somewhat low oil pressure. The engine has a modest 54K original miles and has always run strong and smooth. After the incident, the car cranks but labors intensely in an effort to start and then dies. It feels like it's operating on three cylinders. I had been getting the MAT sensor code periodically (0023, I believe), and thought that a sensor may have gone, thus causing the problem. But upon cranking and looking inside the motor, it appears that some of the rocker arms / valves aren't cranking. I'm removing the valve cover to get a better sense of what the heck is going on.

Do you think I lost the timing chain? If so, is there a chance that valves could have been damaged? I'd hate to think the motor is shot with just a 54K. I haven't pulled the codes yet and will see what they tell me, but any thoughts from the experienced brains out there is greatly appreciated.

Thanks - Roger

[Barney Eaton]

I would check the crank sensor. Something may have vibrated loose and the noise was the harmonic balancer eating the sensor.

The car will not run if the sensor is bad (or mangled)

[Guest rojelio77]

Thanks Barney! I will investigate this. I'm still puzzled by the lack of movement from the valves when cranking the motor. Why would valves not move when cranking? That's why I was thinking timing chain.

[ductune]

None of the valves would be moving if you lost the timing chain. You mentioned some are moving. My guess is you broke a cam so the front cylinders still have function but the cylinders rearward of the point of the break in the cam are not. Never seen this happen but that's one explanation. Another could be bent push rods.

[Guest rojelio77]

Thanks ductune. To be honest, I'm not sure if some or all valves are not moving because I haven't got the valve covers off yet, but will soon. It's hard to fathom a broke cam, but I guess it's possible. I'm concerned that if the chain broke I may have bent some push rods, now were talking new heads..or should I say new head$$...

[Guest Corvanti]

read your codes, then proceed. maybe MAF or (doubtful) - IAC.

if not - since one of my main problems after i got my reatta in march was the crank sensor/balancer (and fuel pump ), i'd check the sensor, as stated above.

curious: how did you check the valves without taking off the cover?

i'm sure more knowledgeable folks with the "quirks" of the reatta will be along soon with info!

[Guest rojelio77]

Thanks for the insight, Corvanti. I spied the valves by eyeballing through the oil fill hole...not too scientific. I've not been able to work much on it today...my employer interferes with my free time. That said, I will pull the codes and see what's up. I look forward to more of the knowledge-base weighing in.

[handmedownreatta]

this is pretty much what my car did when the ecm died.a mechanic told me to tap on the ecm while the car was running to see if the engine skipped or smoothed out.

[padgett]

Almost need to put a finger on a rocker to tell if moving, the "C" 3800 does not have much lift. Can test through the oil fill hole but if cam is not turning then cranking should sound irregular and hear air excaping though open valves.

Frankly I have heard of loose timing chains rattling but not losing a chain entirely, that was something the plastic geared Chevvys and Pontiacs did pre-1973.

[2seater]

I do not believe there will be bent valves or pushrods if the cam or chain decided to retire. The moderate lift and dished pistons should clear each other, although it will be close on the edge of the dish. Very unusual if that did happen. I have never heard of that happening on one of these engines although as Padgett has reported, cam bearing(s) have had issues. If it has difficulty cranking, at the very least, pull all the spark plugs and the front valve cover. If internal damage was going to happen, it has probably done so, but turning the engine over by hand to observe movement would give a little better feel. Even with the lifters bottomed out, you should see approx. 3/8" of movement at the valve when rolling the engine over.

Checking codes and sensors as others have mentioned is a good idea, but I would use caution trying to start the engine if you suspect actual internal engine damage. Check balancer for integrity. Many possibilities unfortunately.

[Rawja]

The timing chain broke on my old '89 Reatta. The 3800 is a non-interference design, so you don't have to worry about bent valves.

[Guest jimmyk]

Removing the front valve cover is really easy, less than 10 min. Have someone crank the engine while inspecting the valves/rocker arms for movement. That will show you if it's mechanical or electronic problem.

My '89 ran really poorly when I got it. I found a broken pushrod for #5 intake.

[Guest rojelio77]

All - Thanks for the input. The news is bad. My pal pulled the valve covers and observed that the front two valves on both sides worked, but the back four valves on both sides do not work, at all. It appears that the cam shaft has snapped in half as suggested by ductune yesterday. The engine is effectively dead.

I can't spend alot of money on R&R an engine for this rig. It's too much dough that I don't have for too little return. If it were a '65 Riviera, it would be different. But it's not. Unfortunately, I have to unload it. The car is up for sale. It's actually in great shape and looks good, if you don't mind the fact that it won't run... The car is in Southern California and always has been. It's 40 mile east of Los Angeles in Upland, CA. Let me know if you're interested in it. I've done quite of few things to it (only to have this happen)...oh well.

Rog

[2seater]

Bummer. I guess unusual things do happen and I, for one, appreciate your posting the actual problem.

[Guest Corvanti]

that sux!

there are several so-cal residents here on this forum, one in La Verne. perhaps they could steer you to someone that might be able to get her repaired for less $$$, or might be interested in picking her up. if i still lived in Pomona, i'd try to help.

[padgett]

There are so many 3800s floating around that it would be much easier/cheaper to just swap engines.

Alternatively a cam replacement is not that hard and can be done without removing the engine or heads. OTOH you mentioned low oil pressure and if the cam bearings are in place (that was a '90 thing) the engine may be generally worn which gets back to plan A.

Just noticed it is a 90 so first drop the pan and see what is in there. If you find pieces of a bearing or two then it is not just a cam replacement.

Edited September 25, 2012 by padgett (see edit history)

[ductune]

Sorry to hear about the cam failure. I've only seen this one other time on a 3800. The likely root cause is a seized cam bearing from lack of lubrication. Once the bearing seizes, the cam gets twisted and fails.

Hope someone here buys it and puts an engine in it. Repairing the old one would require line boring the cam bore to prevent a repeat.

[padgett]

and oversized cam bearings. When mine failed none were available. SUspect a replacement long block or engine would be the way to go.

Mine happened in Indiana on a very cold morning. Dealer said it was the gauge. Drove home to Florida at 70 with no problems but reading 19 psi max. Found bearing shells in pan when pulled.

Have heard of a few others with this problem, all after 50,000 miles, all 90s.

Strange thing is that the cam bearings are closer to the oil pump than the mains.

[wws944]

As Padgett says, there are lots of used 3800s around. If you are willing to do the work yourself, a Pick-N-Pull engine is only about $200-250. Might be a good excuse to upgrade to a 3800 with a supercharger on top.

[DAVES89]

I looked at Car-Part.com--Used Auto Parts Market and there are a number of engines available for $300.00 with less the 100,000 miles on them. Ask the counter guy if they can do the install or can recomend someone. Should cost less then $1000.00 for everything.

Less then the hit on selling a car with a blown motor...

[Guest rojelio77]

Thanks for the tip. I'd like to fix 'er up. I see that there are multiple car types listed when I searched for '90 Reatta, but I presume any of the 3.8L's will do the job. Is my presumption correct? Thanks!

[2seater]

Any LN3/vin C engine should work. Possible there may be minor trim items slightly different if from another make, but all original engine fittings could be swapped on. Almost all full size GM fwd cars of that era were powered by the LN3, as well as many midsize.

[Guest Mc_Reatta]

One thing that I can think of is oil pan may not have mounting hole for oil level sensor so might have to swap pans.

[Guest Richard D]

Since you have already put a lot of work in the car I would look for an independant mechanic shop and a used LN3/VIN C engine, I bet GM built millions of them. Best of luck. The 3.8 has a reputation of being almost bullet proof.

[NCReatta]

I agree with the others. 3800s are plentiful if you want to fix it. Though, if you want to sell it, I'm interested.

Sent from my mobile device using Forum Runner

[padgett]

Buick, Olds, and Pontiac all used the same engine. Just nake sure they are careful and if you buy a complete engine that means with all sensors, manifolds, and ignition. When I bought mine the knock sensor and one exhaust manifold were bent and the ignition and MAF were missing.

BTW if your a/c works the compressor can just be unbolted and set where you removed the radiator without depressurizing the system. Also there is one backwards facing bolt on the transaxle that took all of my extensions to remove.

Start by you and a helper removing the hood and is all simple from there. With the tranny uncoupled it is easy to pull out the top, engine and trans together, drop out the bottom. Just follow the manual carefully and make sure everything is disconnected before pulling the long heater tubes are easy to bend.