View Full Version : 94 N* Eldo - Thought was Head Gasket! WAS NOT! My experience!

08-04-04, 03:42 AM
Here's the story...I'll spare all the things in detail that I've had done to this car over the last 4 years. Most we're dealership repairs, including a ball joint that broke off on the passenger side! In short, I myself have taken on and replaced the starter, every cooling system component, coil packs and do the oil, plugs..etc.

My woes began about 2 months ago while driving home one rainy night my engine hot gauge pops up out of nowhere. I take my exit and get not even half mile and the heater core burst and anti-freeze steam fills the entire car. I had it towed home.

That next morning I set out to bypass the heater core. What a PITA that turned out to be. Something so simple. Problem is where I initially decied to cut the line and then *doh*. I end up using an old cooling line "U" from my now gone s-10 blazer. Everything seemed to be alright. Wasn't full blown heat of the summer, but it was around the corner.

Maybe two weeks later me and a friend are on the interstate and the car begins to overheat. It was terrible. A 30 minute drive took us 4 hours to get home. I didn't let it go to stop engine, I pulled over once it got to 140 or so. It was a long hard night, but I refused to be towed this time.

I start inspecting stuff the next morning. All this is going to come around and tie in to this next part, but it is funny just how close we are sometimes. One thing I notice is that the fan is coming on at 225 (which I believe is correct?), but it's not spinning very fast IMO. Looks like some hamster running around in there to spin it. So, next thing I do is begin to look for an electric cooling fan. AutoZone want's $150.00 I believe. I found a kit on the internet for $75 to rebuild - just replaces the motor and not all the plastic, etc. I was going to go with the kit but I am very impatient with this kind of stuff. I opted to find one locally, in a junk yard. $55.00 and I rolled out. Popped that baby in and...Nope..spinning slow like the other. Now I had asked the guy at AutoZone about the fan relay when I asked for price on fan. He assured me it wasn't the fan relay becuase it was coming on. Somehow I thought to myself that maye so, but the contacts have weakend or what not and is not allowing enough amperage to get to the fan. But, instead begin looking at other stuff. Basically, the fan was still coming on very slow and I just took it as I couldn't remember just how fast it spun, but I mean I couldn't even hear it out the vehicle. I did a garden hose flush, and yes I have learned much about dex-cool, the pellets etc since this all began. At this point, I had still not found the site.

I inspected all the obvious things such as the thermostat (replaced), etc. I pulled the lower radiator hose and I noticed it had the spring in it all rusted and nasty. Broken in pieces. I bought a new lower radiator hose and all my problems had seemed to go away! I was happy.. but.. it was only letting me not overheat if I was crusing 30mph or more. For over a month I dealt with this. I couldn't drive across the river (New Orleans), and I couldn't sit in bumper to bumper traffic. Had to turn the car off at redlights at times, and even then I was getting heat soak like crazy. I was loosing my mind!

Nightime was pretty smooth sailing and the car would get in the 220's, but with no traffic I was able to get around some. Daytime was a little tougher, but if I went somewhere straight from home in the morning, I could make it a llittle further.

** Warning ** Next paragraph may cause crying

One night I go visit a friend across the river. Climbing up the bridge, the car definately warmed up faster. As opposed to crusining and elevated. I go to my destination thought. Temps were in the 130's. The onramp is real close to the actual bridge crossing so I thought for sure I could make the climb and coast on to home sweet home in the 120's. I got over the bridge and the car overheats so fast, I couldn't believe! I mean on the bridge at night, in a bad spot! I am besides myself at where the cooling is coming from and exactly what had happened. A policeman pushes me down the ramp and to a near gas station where I once again get a tow home.

Next morning I take the radiator out.. Well guess what. The radiator wasn't sitting in there 100% properly (probably from one of my prior radiator removals for the tank splitting - happened twice to me also!) . Anyways, I had been pushing the AC switch even though my compressor died. I figured I could use the extra help from the AC fan. Well the fan was just barely rubbing near the bottom of the radiator and casued it to spring a leak. The next day I bring it to the guys who did the tanks for way back when and for $85.00 I was all soldered up and ready for more action.

Once I put the radiator in it was more of the same. Driving around at certain hours and watching I don't get stuck in traffic. Weeks go by. I find this site and I began to read and read. I mean sometimes the same post twice. Page after page. Now I've replaced the radiator cap, thermostat, lower hose and upper is good. Going through parts I find the cut piece of connector that was on the junkyard cooling fan. Somehow I got the bright idea to make a wire and go straight to the battery with it to see how fast that fan REALLY goes! WALLA! That baby is moving now! I get all excited and make a temporary switch through the grille and all seems good in the hood this day. Thinking I had solved the problem I run the wire to the 10A cooling fan mini fuse. Of course I blew it, but I run the fan to the left side and it works. I also noticed that blowing a fuse can cause the "SERVICE VEHICLE SOON" light to come on. Thought the car was alright. I take it on a pretty far trip the next day and was in moderate traffic, but was getting around. Next thing you know, the gage starts climbing. I had to go about 80 mph on the expressway to get it to the high 120's, 130s. But it would immediately propel to the 140's when I slowed. It was no joke. I puked fluid a few times in the situation over the last two weeks. Just barely pulling into the driveway before 150, with white knuckles and wasted antifreeze!

I bite the bullet and decide i'm going to do the water pump. I had let the dealership replace one about to years prior, but it was an aftermarket pump. I'm friends with the service managers, and at the time was trying to save some bucks - probably for more caddy repairs. Anyways. Last week, the same night I win a Northstar Water Pump off of eBay for $41.00 shipped, and I orded an Astro Pneumatic water pump tool from the internet. Wednesday came and I got the water pump, but had no tool. This frustrated me as I already had the car waiting with the pump cover off and everything. EVEN THOUGH the water pump wasn't leaking, I still decided it may be seriously corroded looking at the lower hose housing (was all pitted and corroded on the inside). Finally, on friday a friend came through with a MAC tool for me to borrow! Wonderful. Thank god for the site I was prepared to use a breaker bar. I had to sawzall a piece of pipe and put it over the wrench. My goodness was that pump tight. I also knew to go clockwise to remove it because of reading here on the forums. Finally, after all my mite the pump comes off. Suspicious of corrosion were dead on. The o-ring behind the pump was crumbled to pieces and the pump was seriously corroded. I noticed on the new pump the blades protruded further than just the round metal on pump. Would lead me to believe the aftermarket cheaper one wasn't as efficient becuase it left .5" gap between the impeller and the pump housing where the new pump was another store. Don't you know that the new pump hit on the housing. Enough to where I knew it wouldn't turn. I had to put the pump socket on and kept working it back and further till it wore down some of the aluminum on the pump housing itself. Talk about clearance now! It took 10-15 minutes and I still don't know why it hit, but it did. Once I "clearenced it - wink" I put it all back together. I was careful to hose the housing out very good from any metal that shaved off. If I had known, I maybe would of shaved the housing priot to installing the pump back, but I had know way of foreseeing that. I put it all together and once it again it appears to be doing alright, but is in the upper 120's. It's not rocketing to overheat, but it appeared it could be a possibility.

Saturday night I decide to take the car out and I make a decent 10 mile drive and it didn't even get to 210. It was 11 oclock at night though, and was easy crusing. And the car was started with ambient temperature coolant, around 90 degrees. Even did a few shots and toasted to possibly a non-overheating Northstar!

Sunday comes and I have to bring my son home from our weekend together. Car is 120's but it's holding. It's hot and daytime. No traffic. I stop at my cousins with my aunt and she forgets her keys and runs inside. That takes a few minutes and now the car is edging 130. By the time I dropped my aunt off at home and made it my house, the car had hit 150 and puked. I was D I S G U S T E D. This is the part where all the post about blown head gaskets start sinking in. Makes me week in the knees. I planned on getting it to a mechanic so he could test for head gasket failure. I just was hanging on to any hope of it not being that. All my indications where leaning to it however.

At this time I would like to point out a few things though. 1994 N*, 156K and I was loosing no coolant. None leaking. Car runs smooth although I've replaced ignition coils and wires. But it leaks no oil and starts/drives fantastic. In a last ditch effort to be in denial about the head gaskets I pulled the cooling system all apart again. I decided I was going to take the radiator to the Radiator shop and ask them to check my core since it was the original radiator, although the tank had been replaced twice. I bring it to them and the owner tells me that when they did my tank a few months back that they also routed it out ( standard procedure). He said he would just be taking my money and it would not fix my problem. I appreciated that honesty and the place is Kerb's Radiator in Marrero, LA. He suggested air may be in the system. Another mechanic told me the same thing. So there I am with my radiator in my hand which I didn't need to take out, and two mechanics suggesting air.

* Dealership gotta get theirs! *

Well... stupid is as stupid does. I decide to wire up my AC fan to come on when I start the car as well. This way I can have mad air being blown and will give me a little extra temp and time! In the process of all this I decide to take the thermostat out again, even thought it is new. I'm just hard headed about them. HOWEVER. I had noticed a bolt in the housing that kept getting tight and was no longer able to be snugged or tightened by hand. Finally.. * SNAP * I break off one of the bols in the pump cover. INSERT profanity HERE. @*(#&*@&^. That cost me! To the tune of $37 for the pump cover, $10 for the gasket, and $10 for the bolt. I borrow my aunts car and with radiator in the trunk i'm now talking at the dealership with my service manager friend. I let him know old nelly is still alive, but barely. When I tell him all what's going on he begins to tell me about the time serts and bolts pulling phenomenon. I had read that here, and him telling me the same thing was just killing me. Even with my little $60 of parts, I felt they may be in vain. However, one bolt in the water pump housing for the lower hose is NOT going to cut it. I must admit it looks super sweet, cleanest things on the motor now. Looks like 2005 water pump cover ;) . Anyways. I tried to locate him after I bought the parts so I can get him to tell me where the Fan Relay is located. Not where, but which of the 4 is it. If any of you know I would sure appreciate it. I have a new $30 relay sitting in my glove box.

I came home and put everything back together and broke the news to my friend and family.. pretty much that it will cost me $3500 or so and pulling the motor out to fix. Yesterday was a drab, dreary day for me.


Last night I started reading these forums again. This time taking in more info about the barsleaks. That night I went to walmart, almost midnight and bought 3 tubes and some dex-cool. I figured in the morning I would empty it good, install the tubes of Barksleaks into the lower hose, and fill with coolant and distilled water mixture. That would be that. Blown head gasket, time to live with overheating. ALL MY LUCK CHANGED. I came across a post that was about a guy with overheating who had also wired his electric fans to ignition. I don't know if it was Bbob or not, but a helpfull member suggested he double-check the direction the fan is blowing. That stuck in my head and I was so curious that I wanted to go outside at 2 am to check it but opted to go to sleep instead. This morning I do just that. I could feel air, but low and behold I put a piece of paper further down and the fan SUCKED IT UP! I was pushing air towards the radiator! And now I was doing it with both fans! I reversed the fans, added my barsleaks and filled with coolant. Thank the heavens! My Caddy is ok! I drove it for 30 minutes this morning and couldn't get it over 210. Then I left it running at the gas station while pumping gas. Still nonstop from the morning and i did manage to get 228 while sitting there, but it would go no higher and went to 219 soon after acceleration. Few hours later, 95 degree weather. I take it on a 5 mile journey, 3:30 in the evening. It only went to 198. Didn't even reach 200, and hasn't since.

After all of this I am more enlightened though. I am paying much more attention to the maintenance of my cooling system, and I do have the urge to floor the car so much. I used to abuse the power, but with the wakeup call of high mileage and the fact that the bolts could pull from the block or head gasket leak, it's just not worth it. Yes I will drive fast and drive hard, but gradually. No more screeching tires even though I know it loves it and has the power.

At this point the fans are still wired to ignition. I'm still looking for info on which relay is for the cooling fan and I guess I'll install it. Is there any bad effect from running the fan 24/7 when car is started. And what temp is the fan supposed to kick on. Mine was coming on at 225, just not strong. I believe this to be the correct temp? I sure like these ultra cool temps I'm having now tho.. running 190 - 200.

Going to attach a pic of my pump just so you see i'm not just whistling dixie.

Ken Seliga
08-04-04, 08:17 AM
Reference to your fan question, I posted a reply to "coolant temp 250" in this forum on 07-29-04 which give the relevant numbers..On my 95 ,the fans are controlled by relays switching both fans on LOW or HIGH , dependent on the temp. Its probably not a good idea to wire around the existing circutry as the fans are also controlled by transaxle temp..BUY A GENUINE GM SHOP MANUAL>>>they are available on the net or direct from the printer...This is one of the most needed and the BEST set of manuals I have ever used..and I buy a shop manual (NOT CHILTONS) for all more cars..Even at $120 you would have saved yourself a lot of headaches...The manual shows location and operation, diagnostics and tests of the fans...

08-04-04, 08:31 PM
Per '97 service manual

Both fans operate together, always at the same speed. The PCM commands LOW SPEED operation under the following conditions:

- Engine coolant temperature exceeds approximately 229*F.
- Transmission fluid temperature exceeds 302*F.
- A/C operation is requested.
- After vehicle is shut off, if the coolant temperature at key-off is more than 304*F, and system voltage is greater than 12 volts, the fans will stay ON for 3 minutes.

The fans will switch to OFF when the coolant drops below 216*F.

HIGH SPEED operation:

- Engine coolant temperature reaches 234*F.
- Transmission temperature is more than 304*F.

The fans will switch from HIGH to LOW when the coolant drops to 229*F.

08-04-04, 10:59 PM
Thanks for the info! Low speed must be pretty darn low if thats the only speed I was getting. Thing that concerns me is that it was spinning slow no matter what the temp was. So am I to believe the low speed relay was kicked in also at temps over 225? Also, I did buy a relay but have not replaced any yet. I found the group of 4 under the fuse box under the hood on drivers side. Not sure which of the 4 it is and I know I could do process of elimination, but right now i'm just so happy to have a smooth running caddy that i'm taking it easy! I know I went around the fan circuitry, but in my defense I haven't hacked not one factory harness in doing so. THe plugs are just as they were and no factory harness has been harmed in the making of this repair ;) Anyone want to tell me which is the high speed relay I'll slap the new one in and plug it up and see what happens. I will say this though... I changed my sparks plugs this morning and my 156,000 mile Eldog is running so smooth. I have 1 year old wires, new coil packs. I dare say it, but the car seems to be running as good or better than when I got it 80,000 miles ago. There is no hesitation, rough idle.. nothing. It is running super smooth. All my blood, sweat and tears have paid off.

Oh.. one thing I forgot to mention and don't know how I could..when I went to do the water pump I took off the elbo for the air intake and move some wires out the way.. when I did, the loom just broke off and felt real brittle. I had a group of about 12 wires all melted together. All of them.. Not one was excluded and some were very bare. This is a large round plug connector located under the air elbo. It was laying on my transmission. I repaired the harness myself. One problem that has gone away since I did is a slipping transmission. Usually upon first starting up and driving. It would slip, now it doesn't. I thought it would fix my speedometer, but sometimes the speedo goes to zero while cruising. My blower for the ac/heater used to come on by itself. Used to think it was a ghost. It has stopped since the repaired harness. So, without having a manual I don't know exactly what all those wires were, but i'm sure glad I found them!

With the fans wired to ignition i'm having a hard time getting the car past 198. 210 is hard during the day right now, just as long as i'm cruising. I actually think it's running cooler than stock right now, with the two fans on constant HI. Yes, I will put it back, but like I said - i'm just so happy. I went from one extreme to another. I was 90% sure it was the head gasket! Just goes to show. I had really gave up. Went bought the barsleaks and was preparing myself mentally for the fact that I have a car I could only drive short distances, etc. Then I read the post about double-checking the fan direction. I'm definately not a machanic by trade, but I don't care if it took me 2.5 months to figure out. They were rough and frustrating, but I learned so much and the end justified the means.

08-04-04, 11:18 PM
Low fan should be on 229-233 deg. Hi fan 234+
From the way you discribe it your low fan speed sounds way to slow. Maybe a failing fan motor? Does is spin freely by hand?

08-04-04, 11:27 PM
Ranger, my original thought was the fan motor itself, but was not. Hooked directly to the battery it works wonderful. Do you know if the same relay controls both the high and low speed or is it two seperate? If they're seperate, then both relays have failed. If they're one relay, then the contacts are very week. Unless of course it was something other than the relay. I'm not out the woods, but i'm not overheating anymore either, so I can approach the fix methodically. I cringe when I see "234". I'm gunshy now. After driving for 45 minutes around town and then letting it sit as I pumped gas it got to 228 and I sweating it. Never got hotter than that thought and soon as I pulled out the parking lot it went down to 219. Life is good..... :bouncy:

08-04-04, 11:31 PM
Well, I am not positive but off the top of my head I think there are two. I would have to check my service manual but then again mine is a '97.

08-04-04, 11:37 PM
Ranger, thanks for any info. In regards to a post in someone elses thread, you touched on the fuel pressure regulator and/or leaky injectors causing poor fuel economy. Can either do so without having any noticeable effects on the car. Netherwards, if my fuel pressure regulator is dumping extra fuel, would it cause the car to run badly or just decrease my fuel mileage. It's running alright is why I ask, but at today's gas prices, would be nice to get it back to 18-24 mpg like when I bought it... this has been an issue for quite some time now. I've replaced coil backs, etc. And it did help, thought it was it. Car was running very bad.. dealership replaced a coil and it straightened it out. However, the economy only went up 1-2 mpg and a month later the car was running rough again. I have replaced all my coil packs myself since then and just want my economy back at this point. Willing to try anything. Especially with some of my parts being original 156,000 miles parts. Is it hard to change the FPR, are they expensive? Thanks in advance.

08-04-04, 11:46 PM
I am not sure about the effects. If they are leaking badly it may have some effect on idle. It would start ok cold but be hard starting hot. Not sure about price but I think I heard someone say $65 for FPR but don't quote me. I beleive it is an easy change though I have not had to do one yet. It is on the fuel rail in the intake on the '94. To check it, remove the intake cover, turn the key on but DO NOT start the engine. Look for fuel leaking out of the nipple. If you see any, replace FPR. Same proceedure for the injectors except you'll have to pull the fuel rail and watch for leaky injectors with the key on (fuel system pressurized). I'm leaving work now, g'nite

08-04-04, 11:50 PM
Excellent. Thanks for all your help. With all what i've been through recently, i'm going to back burner lifting the intake. Believe me, if I new for certain my fuel economy was lost there I maybe would take it on tomorrow, but not knowing for sure.. i'm pretty well spent after this latest round. I have however replaced the starter few years ago, so i'm not afraid to life the intake.. I just don't want to see my baby in pieces again so soon.. Good info tho! Something for me to consider.

08-05-04, 12:03 PM
I don't think you have to lift the intake. Just the top cover on the '93/'94 to inspect the FPR and injectors. If your milage has decreased both of those would be very suspect.