GaryB Posted April 11, 2004 Report Share Posted April 11, 2004 I have a 1994 STS with 107,000 miles. The engine runs fine on the streets and on the highway. However, when I take the car into the mountains the engine overheats. I also have to add coolant every couple weeks. I suspected the head gasket and the Caddy Dealer confirmed this. I normally do my own work on the Caddy. The dealer said I would need to add Time Serts. This is a job that I'm not looking forward to doing. My first option is to have the dealer do the work. This would cost a a pretty penny and he not guarantee that a Time Sert wouldn't be damaged rendering the engine unless. My other concern is that I'm not the original owner and I'm not sure what condition the rest of the engine is in. A second option would be to get the engine rebuilt or purchase a used engine. Again, I'm not sure of the risk of getting another bad engine. I know these engines are touchy and proper care is a must. The last and final option is to by a new engine, have the dealer install it and get a warranty with it. The car is paid off and it's not my only vehicle. The body, interior, transmission, and suspension are all in good shape. I could by a new vehicle but this car drives like a dream when it's running. I wont spend more than 25,000 for a new car and at that price ther is no way in He_ _ I'm going to get the same kind of ride. Is this car worth keeping? If so what would be the best option for me or if you have any other ideas I would be happy to listen. GaryB Link to comment Share on other sites More sharing options...
JasonA Posted April 11, 2004 Report Share Posted April 11, 2004 Gary, I think it's worth keeping, and you mentioned that it wasn't your only car. So could the car be down for a month without you needing it? If you have a garage, I'd just lay it up in the garage and do the work yourself. Work slow, no pressure; you have another car to drive. And the way I read it, you were considering investing in a new engine anyway, so if you REALLY mess it up, the only money you're out is a few hundred bucks for the head gasket set and Time sert kit, and a tow to the dealer. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
Barry94 Posted April 11, 2004 Report Share Posted April 11, 2004 Hi Gary, I have a '94 STS and had the same condition about two years ago. With information obtained from the very talanted people from this site, I decided to do the job myself with the engine in the car. It took me a week, however, I installed Time serts, with new new head gaskets and the engine has been working perfect since. You didn't mention your skill level regarding doing your own repairs. The job is fairly complex, however not beyond anyone with some past back yard skills. I'm not a mechanic, just a computer consultant that likes to do their own repairs. If you have a manual and some common sense, then you can do the job yourself. If you do decide to attempt the job, you can count on the people here to give all the assistance you need. Barry 2008 STS V82016 Colorado Z711970 Corvette LT-1 Coupe Link to comment Share on other sites More sharing options...
Greg P. Posted April 11, 2004 Report Share Posted April 11, 2004 If the rest of the car is in good condition, it's probably worth doing the head gasket repair. In any case, I'd do the head gasket repair before I'd replace an entire engine. There is no point in replacing and entire engine unless you really suspect there are other major problems. For sure, the timeserts must be installed as part of this repair or else you are asking for big trouble. Link to comment Share on other sites More sharing options...
growe3 Posted April 11, 2004 Report Share Posted April 11, 2004 If you have ever rebuilt an engine or feel confident in this area, have basic mechanical tools and good skills you can certainly do the work yourself. You will also need an engine stand to mount the engine on for the repair work. Do not let the Timesert requirement put you off. It is a little tedious but straight foreward job. You will need the proper kit to do this job. I bought mine from the people that make them at www.timesert.com The kit comes with ten Timeserts, you will need to request ten additional Timeserts so that you can do ALL of the head bolt holes. They come with comple instructions and all you need is a 1/2" drill motor to install them For a dealer to express no/low confidence in this repair would make me not want to trust them with the car. I would recommend the following: First and perhaps most important, get the Helms service manual set. You can sometimes find a good used set, but if you do not want to wait for auctions to close just buy a new set; about $90. You will be paid back many times over in avoiding wasted time, damaged parts from improper assembly or disassembly. Note these manuals cover the entire car not just the power train. Helms Service Manuals The engine can (and in my opinion should) be removed from the top, for the head gasket repair. Others have had success removing the engine and transaxle cradle, but I feel this is a much harder method. I would strongly suggest that you not try to do this job with the engine in the car. The last engine that I removed, I used an engine load leveler (about $35), this made it easy to manipulate the engine out of the engine compartment. (The tight spot is at the rear when lifting.) There are a few times to take special care before replacing the heads on the engine that have been explained on this site, so when that time comes place a post here or directly to me if you wish further explanation about this. Do not buy any replacement parts until you have the engine out, heads off and have made a list of all parts that you need. I recommend that you only use the OEM parts. Then buy the parts online. I have used the following two sources for the all OEM replacement parts. You will probably spend about $300 - $400 in parts if you replace all of the normal gaskets and other miscellaneous items that need replacing. http://www.partszoneonline.com/index.php (My prefered source) http://www.gmpartsdirect.com (another good source) As noted by jadcock, allow yourself plenty of time so you don't have to rush. It's really not that bad of a job, but it is somewhat time consuming. If you like doing your own auto repairs, the successful completion of a Northstar head gasket repair will give you some bragging rights. Good luck and as others have said check back with questions as you proceed. -George Drive'em like you own 'em. - ....................04 DTS............................ Link to comment Share on other sites More sharing options...
adallak Posted April 11, 2004 Report Share Posted April 11, 2004 check this out for manuals http://www.factoryautomanuals.com/cart/customer/home.php The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
GaryB Posted April 12, 2004 Author Report Share Posted April 12, 2004 First off let me thank you all for your response. They made me feel better about this whole situation. My mechanical skills are good. I'm a project manager with a background in mechanical design. I have a lot of experience with tools and working with my hands. I have little experience with cars though. My only experience is with the Cadillac. So far I have replaced the battery, the starter, the alternator, the spark plugs and one of the door locks. I currently use the Chilton Manual. I do have a garage but it won't be available to me for another month or two. Having the car out of commission until September is no real big deal as I mostly ride my motorcycle this time of the year. I have decided to attempt this repair. I will mainly do preparation in the coming months. I have already ordered the Helms Service Manual. I will order the Timesert kit next. I will also look in the archives and print out all the previous info on this procedure. Once the manual comes in I will review all the information, note and post any questions that I have. Hopefully by that time I will have the garage available and I will do the work. I will wait until I have the manuals and all the previous posts before I decide if I will try the procedure with the engine in or out of the car (please fill free to comment on this issue). I'll post up as soon as I read the manual as I know I will have a few questions. Thanks guys, GaryB Link to comment Share on other sites More sharing options...
Ranger Posted April 12, 2004 Report Share Posted April 12, 2004 Gary, You may find this of some interest. good luck. http://caddyinfo.netgetgoing.com/howto/nsrepair.htm Link to comment Share on other sites More sharing options...
CaddyChris Posted April 12, 2004 Report Share Posted April 12, 2004 Hey, I just registered but I have been a long time reader. This post could not come at a better time. I have a 94 sts, 237,000 miles, original engine and trans. This car runs great, although I ve only put 5000 miles on it. Now I'm running into some quirky problems... need some opinions: First, the car is running hot: I am not sure if it is using coolant, it's definately not mixing with the oil. All aspects of the cooling system have been ruled out as a possibility( took thermastat out, took radiator apart, replaced water pump) This is what it did before we put a new style water pump off a 98 Northstar on the engine. It would consistantly run at 225 F. On the highway, anything above 2000 rpms would produce a steady rise in temp. Hard acceleration (4500-5000) rpms in 3rd gear to 80mph will produce a rapid rise in temp from 225-255 until it would overheat. The temp would stay steady unless cruising at 55 mph (1750 rpm) Ok, so this sucked, i could drive it around town , but not the way i want. ANyways, my dad is a mechanic, he has 3 northstars sitting in the garage(each with a different need of repair), We put a new waterpump and housing from a newer northstar ( bigger fins=more water flow) Now the car is running better, but , upon hard acceleration rises to 235 and then comes back down to 215-225. My dad has another 95 sts and it runs at 200-210. So, here is my question for all of you great caddy fans. The body is good, the interior is ok, the car was bought for 1000, I cant do the work. My dad isnt very enthiustic about it. Do you think there is internal problems with this engine (head gasket or cracked block or something) Also, my Dad says they always drop northstars out the bottom with the subframe, he has a garage with an engine hoist, it's possible ( and easier? ) to take it out the top? Thanks so much. oh, here are my cars. thanks again. Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
CaddyChris Posted April 12, 2004 Report Share Posted April 12, 2004 the cars are on this website if you are interested.... the 67 deville took 3 yrs and a whole lot of work to restore. I love to drive it around tho... it was worth it. http://www.pages.drexel.edu/~clp32/home/index.html Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
JasonA Posted April 12, 2004 Report Share Posted April 12, 2004 All aspects of the cooling system have been ruled out as a possibility( took thermastat out, took radiator apart, replaced water pump) Did you put the thermostat back in??? If you're running it WITHOUT a thermostat, that's likely the cause of your overheating. Put the thermostat back in, verify the proper operation of the water pump drive belt tensioner (to make sure the water pump is spinning at the proper speed at all times), and drain/refill with a fresh 50/50 mix of coolant and water. You also need to check to see if it's using coolant or not. That would be a good indicator that something else is wrong inside the engine. Have you done a compression test of all cylinders? Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
growe3 Posted April 12, 2004 Report Share Posted April 12, 2004 ...... my Dad says they always drop northstars out the bottom with the subframe, he has a garage with an engine hoist, it's possible ( and easier? ) to take it out the top? Yes, you can definitley take it out from the top. For the most part it is no different that any other engine removal. When lifting the engine out the tight spot is at the rear. The last one I pulled I used an engine load leveler ($35), and it was easy to control the engine angle, to clear the heater barrier. Running hot at higher speeds and normal at low speeds sounds like poor circulation. Slipping water pump drive belt, tensioner not working freely to apply full tension to the belt, debris blocking radiator from full air flow?? Do not attempt to do the head gasket repair without the Helms Service Manuals, they are about $90 for the two volume set and will pay for themselves by saving you from wasted time and damaged parts due to improper assembly or disassembly. While I normally use after market, high performance parts to build my engines, for the Northstar I only use OEM gaskets. -George Drive'em like you own 'em. - ....................04 DTS............................ Link to comment Share on other sites More sharing options...
PAUL T Posted April 12, 2004 Report Share Posted April 12, 2004 Make sure the hose from the waterpump to the surge tank is not blocked or pinched it will cause the pump to lock-up. Link to comment Share on other sites More sharing options...
CaddyChris Posted April 12, 2004 Report Share Posted April 12, 2004 Ok, thanks for the posts guys, a different thermastat has been installed, ( it was already in place with the new water pump housing). It still exhibits the same behavior. My plan is to see if it is using coolant and see how long it will go without acting up. The radiator has been taken out, we took the side tank off and blew it all out, it wasnt really clogged at all, we also blew into the engine as much as we could with a pressure washer to make sure there were no blockages. All the hoses are clear, even the small one going across the front of the engine has been blown out. What i'll probably end up doing is driving it until it gets worse or when I realize it is definately using lots of coolant. I mean this is a rapid rise in temp before the new waterpump was in stalled it went from 215-255 in about 25 s. This really worried me, It still exhibits the same behavior although not nearly as bad. I'm going to play it by ear and when things get really bad I'm going to do an engine job. Thanks again guys. Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
adallak Posted April 12, 2004 Report Share Posted April 12, 2004 GUYS, YOU HAVE NEVER MENTIONED FANS! ARE YOU SURE THEY TURN ON WHEN THE TEMP. GETS SOME 225 DEGREES? The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
adallak Posted April 12, 2004 Report Share Posted April 12, 2004 besides, there are dozens od ways to lose coolant. it might be head gasket or something more common and easy repairable though not that easy to figure out. just my 3 cents The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
CaddyChris Posted April 12, 2004 Report Share Posted April 12, 2004 we got out the svc manual and the fans turn on low speed at 106 C and high at 110 (approx 220 and 23?) we checked them and they turn on appropriately. THanks. Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
GaryB Posted April 23, 2004 Author Report Share Posted April 23, 2004 Here is my update on my 94 STS. I ordered and received the Helms service manuals. WOW, that's a lot of information! I also downloaded information regarding the Time-Sert from their web site. They offered two kits, a first time kit and a second time kit. This got me thinking that I should wait till I have the heads off before ordering the kit. I bought the car used and I'm not sure what I'm going to find once I remove them. Unfortunately I have had to put the work on hold. My second car was smashed by a Taxicab while parked on the side of my house. Once the rain stops I’ll be able to ride my motorcycle to work and I can start the repair. Barry, I do have a couple questions for you regarding your repair. Did you have to remove the front cover in order to reset the timing or did you figure out a clever way to preserve the secondary chains? Also, what should I watch out for during and after removal of the heads? The manual makes mention not to place them flat or you will damage some of the valves. Did you lay them on their sides? You mentioned that you used an air ratchet to drill the holes for the time-serts. I do not have an air ratchet or a 90-degree drill. I will need to purchase one. Which do you recommend? The helms manual makes reference to special tools. Do I need them and if so where would I find them? I hope to start tearing down the engine in the next week provided the weather holds out. I will continue to post up. I’ll try and document the process and post pictures. Any how to or watch out for are welcome at this time. Thanks guys, GaryB Link to comment Share on other sites More sharing options...
CadiKing Posted April 23, 2004 Report Share Posted April 23, 2004 Hey Gary B! I, for one, cannot wait 'til you get started! Good Luck on the project, you obviously have the talent to do the work. jim Link to comment Share on other sites More sharing options...
Barry94 Posted April 23, 2004 Report Share Posted April 23, 2004 Barry, I do have a couple questions for you regarding your repair. Did you have to remove the front cover in order to reset the timing or did you figure out a clever way to preserve the secondary chains? I did remove the front cover. The chain tension device is the problem. It's on a ratchet. the slightest drop in tension and it will extend. It cannot be compressed again unless the lever on it is released. Prior to removing the timing chain, I put a tiny dab of white paint on all the gears and chain relationships. So when I reassembled I could quickly see if all sprockets and chains were back in the same place. Also, what should I watch out for during and after removal of the heads? The manual makes mention not to place them flat or you will damage some of the valves. Did you lay them on their sides? With the cams still in the head, there will be some valves open, so they are warning you about this. You can use a couple pieces of wood under the head (where the valves are closed) or put the cover back on and place it upside down. You mentioned that you used an air ratchet to drill the holes for the time-serts. I do not have an air ratchet or a 90-degree drill. I will need to purchase one. Which do you recommend? The helms manual makes reference to special tools. Do I need them and if so where would I find them? You didn't mention if you are removing the engine. If the engine is out, then you don't need the 90 degree drill/ratchet. If the engine is in then it's needed to do the rear bank. If you have "air", then a 3/8 air ratchet is very cheap and handy to have for other jobs. If you have no "air", then perhaps a 90 degree attachment to a regular drill maight be a cost effective way to go. As far as special tools go, the only one would be the puller (three arm) for the front pulley. Any discount tool supplier will have one. Mine is a "made in China" one, very cheap. You'll need lots of sockets and extensions. Barry 2008 STS V82016 Colorado Z711970 Corvette LT-1 Coupe Link to comment Share on other sites More sharing options...
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