: Coolant Loss

10-31-03, 11:27 AM
My Caddy is down for the moment. On my drive to school, the temp gauge started rising, and then kept rising, and continued on until it buried!! The ac compresser disengaged to protect the motor, warning lights came on, car told me to idle it. I pulled off, popped the hood, to find the motor wasn't even all the way warmed up. But, I had coolant dripping down onto the right axle, was splashed on both rt tires, and a puddle rapidly forming. I think I saw one of the hoses leaking, but couldn't tell from that angle. When I get home, I'll probably get under the car and look. So, any advice on what I should do before and after the repairs (which I will be doing myself) Any kinds of bleeding of the coolant system, etc?

10-31-03, 09:24 PM
Usually there isnt much to do for bleeding the coolant system, except to keep filling until its full..... youll probably see foam in the coolant, which is just air... Let the bubbles go away and then keep filling...... Usually this is easier with the Tstat OUT......

You said it wasnt fully warmed up, but the engine was overheating according to the guage..... That doesnt make any sense......

Also, if you find its a hose thats leaking, I would advise to replace ALL hoses while your at it..... Dont want this to happen again!!!!

11-01-03, 12:12 AM
The reading was coolant level high, and the temp gauge spiked very fast.

11-01-03, 09:50 AM
So you checked something on the on board computer?? Something that indicated that the coolant level was too high, when in fact you were LOSING coolant??? I guess Im having a hard time understanding, as this seems very contradictory......

11-01-03, 12:48 PM
Ok, sequence of events. Driving down the road... at 100 mph. I notice the temp gauge making a rapid climb, so I let off the gas and begin coasting. The temp gauge continues, and the DIC displays "AC cut off for enginre protection" "Engine coolant temp high" "Idle engine" All in very rapid succession, and the engine temp gauge is now buried in the red. I pull off the road, pop the hood, shut the car off, etc. I see my passenger tires are wet. I know I hit no puddles. Looking in the engine, next to the pulleys on the pass side, and down below, I see a fluid dripping down onto my axle. Look under, it's red fluid, dripping at a high rate. On the pass side is some red fluid as well. I start to feel the motor, to see if the motor truly is hot. I touch the manifold, it's still only mildly warmer than outside air. Airbox is still only warm. I hold my hand over the front head. Feeling some heat, but not even to the degree I normally feel under optimum temp. So, feelin gutsy, I gently tap it, and eventually press my hand to it. Hot to my skin, but not dangerously hot or anything. Not a overheated motor, or even hardly warmed up motor.

11-01-03, 12:53 PM
Ok.... Gotcha!!!!! :thumbsup:

It appears as if the computer detects when coolant is low that it assumes its overheating...... And then adjusts accordingly.....

Id check <obviously> your hoses...... Then, your temperature sensors, and Tstat (although it doesnt seem if its bad, but Id repalce it anyway, its cheap).....

I assume Dex-Cool is red.....

11-01-03, 05:52 PM
Dexcool is red, poor baby bled out.

11-01-03, 10:14 PM
Have you started the diagnosis?? Id be interested to see what happened..... And how.....

11-02-03, 10:38 PM
Not yet. Been a busy weekend.

11-04-03, 07:07 PM
Ok, I jacked her up, and found this one hose, not connected to anything. When I load more water in, and leave this in it's original place, the water poured through.


11-04-03, 07:54 PM
Ok, I jacked her up, and found this one hose, not connected to anything. When I load more water in, and leave this in it's original place, the water poured through.


The links dont work..... Could you like them with the IMG code??? Im really interested to see what thi is!!!!!!

11-04-03, 08:02 PM
Well, that went like a lead balloon....

11-04-03, 08:10 PM
Curses..... I guess you can resize them and put them in the photopost for the time being.......

11-04-03, 08:29 PM
Hell with all that. http://www.geocities.com/shadowlvr400/ I don't use this geocities page much, but at the bottom of the page. There ya go.

11-05-03, 09:43 PM
That looks like the overflow tube. It comes off right at the radiator cap. If the engine overheats or overpressurizes the antifreeze gets blown out towards the ground.It shouldn't come out of that normally, the radiator cap covers that but the spring on the cap can be forced up by pressure and let antifreeze out.

Several things can cause it. Worst would be blown head gasket, then bad thermostat, bad cap.

11-05-03, 11:06 PM
Ok, drove it again, and have learned a few more things. 1, it's not a head gasket. The motor itself isn't leaking, the fluid is coming from under the resevoir, so I have a sneaking suspicion that it's the return line from the radiator.

The car holds its water under normal, gentle driving, for the most part. When I stomp the gas, it bleeds out badly. It is definately coming from somewhere below the resevoir. So, I need to figure out what's under there.

11-05-03, 11:22 PM
How do you know it's not a head gasket?

11-06-03, 08:37 AM
The head gasket is part of the physical motor, is it not? This fluid is coming from a spot distinctly not connected to the motor.

11-06-03, 09:24 AM
That hose is directly connected to the engine.
It is at one end of the cooling system and it is a continuous system.
If you have a leaking head gasket you have a source of pressure into the cooling system. The antifreeze will come out at the point of least resistance which is the overflow tube.
The antifreeze coming out under load is a pretty strong indicator of a bad head gasket.

11-06-03, 10:14 AM
It might just be a loose hose clamp or a broken hose.....

Im sure youve done all the tests to see if the headgasket is bad already, right?

11-06-03, 11:51 AM
I just fixed a slow but persistent coolant leak on my '96 SLS. Turns out it was the water pump bearing/gasket that was letting a small trickle of coolant by under full pressure, especially noticeable when it was at full temp and shut off. Replacing the water pump fixed it right up.

If you do this, make sure to carefully clean away all the deposits from the water pump cover/themostat housing gasket and surface before putting it all back together, and torque those bolts carefully. While you're taking it all apart, might as well make sure the water pump drive belt tensioner isn't squeaking/squealing/squawking and that the belt is in good shape. A new belt and tensioner for the water pump probably runs about $50 total.

Water pump at AutoZone was about $65-$70. Borrowed the tool to remove the water pump from AutoZone for $15 deposit. Replaced the thermostat at the same time for good measure (why replace the coolant twice?) for another $10-$15. No more leaks and it was a good opportunity to flush and fill the system with new bright orange DexCool at about 60/40 mix with distilled water.

Good luck :wave: as always and

11-06-03, 04:59 PM
At this point, I haven't done any other tests to see if it's a bad head gasket. Anyone want to tell me those tests?

(Side note, if it is a bad head gasket, I'm going to ave to just do a cheap patch, and carry water with me at all times. I can't even begin to afford to replace or repair a head gasket. Unless you all know how. If I have to pull the motor, basically the car will just have to live with it. Though I am a bit bothered that this came on all at once. Went from no leaking at all, to royal problems under hard gas.

11-06-03, 05:03 PM
The basic stuff I was referring to was like oil in coolant, water in oil, sweet smelling exhaust (not from NOS :D ), and obviously it seeping donw the heads.......

Theres been quite a few good threads here about the headgaskts, it may not be a bad idea to peruse those......

11-06-03, 10:18 PM
None of those have occurred. No oil in the coolant, no water in oil, and the only event of a sweet smell behind the car was when I sprayed my buddy's car with coolant as I blew by. He got the sweet smell, probably because his car was hosed down with it. :)

Aurora By Olds
11-06-03, 10:39 PM
Though I am a bit bothered that this came on all at once. Went from no leaking at all, to royal problems under hard gas.
I haven't read anything else but this (it caught my eye). It could very well be a headgasket. Mine began suddenly one day under hard driving. After a good run, it looked as though coolant had been spewing out the surge tank cap. After a long investigation, I found out that a head gasket is leaking exhaust gas into the cooling system, causing it to be overpressurized only under high RPM's. Mine had the green coolant though, and was never properly maintained before I bought it at 82k. I will be doing the gaskets myself, and with the materials and time-sert kit, it should be around $500 all together if all goes well.

11-06-03, 11:32 PM
Get your engine leak down tested. As your watching the pressure gauge, keep an eye on the tank. If you suddenly see bubbles, you found it. Also, leakdown tests are a good idea on an engine with stresses such as yours to check stuff like valve sealing and ring sealing.

11-06-03, 11:35 PM

Couldnt have said it better myself!!!!!

11-08-03, 01:49 PM
Here's some more info. Sitting in the bottom of the resevior, is a thin layer of some sort of dirt, or silt deposit. Seems a bit slimy, but can't get enough to really tell. I'm going to try a few tests later today, including revving the motor, and seeing if any water shoots from that release valve.

11-09-03, 12:47 PM
And the oddity continues... I refilled the resevoir, went out and got a snack and came home. I did open the car up, went ahead and stomped the gas. She kept the coolant. Let it cool, and then opened the resevoir. As soon as I opened the cap and pulled it off, all the coolant leaked out. This continues to be weird.

11-09-03, 01:07 PM
I'm beginning to think that for whatever reason your cap was loose to begin with. Because now as you found out, she seems to be holding pressure just fine.

11-09-03, 09:47 PM
But then why did it leak all my coolant out as soon as I took the cap off?

11-09-03, 10:51 PM
Maybe I missed something, how long did you let the car cool? If it still had pressure in the system from being warmed up it would have forced the coolant out and all over it's surroundings. Try this, while the car is cold before you go anywhere for the day, remove the cap to verify no pressure in the system. Put the cap back on and start the car letting it run for one minute. Shut it off and remove the cap again. There should be no pressure as the coolant has not heated up and expanded yet. If there is pressure, it is unfortunately coming from the combustion chamber.

11-09-03, 10:57 PM
This guy is all over it!!!! Great info!

11-10-03, 08:25 AM
Dave, the car got to cool overnight. I didn't actually get around to opening it the following afternoon. And as I said, why would the release of pressure cause all the coolant to drain out? And not from that release hose I found before. What kind of pressure regulators/valves etc are there in the coolant system?
Add to that, something squeeks really badly when I start the car. It's on the passenger side, where those belts and pulleys are. Could it be a water pump?

11-10-03, 09:08 AM
It MIGHT be the water pump.... Obviously something is leaking on the belts causing them to squeak, and after a few seconds it goes away......

Ther really arent any regulators or anything.... About all there is, is the water pump, the radiator cap and the Tstat...... Everything else is just a bunch of passages.......

Now, why would the release cause it to spill?? Im not sure, sorry...... :(

11-10-03, 12:45 PM
The thermostat controls the pressure in the cooling system. It may be marked on the cap, 15lbs or 22 lbs, something like that.
Bad headgaskets generally seal when the engine cools and the cap retains some pressure. Remember, there is a huge difference in pressure between running and sitting still but hot.
When you take the cap off the pressure left in the system can blow some antifreeze out.
You will not get water in the oil until the head gaskets are totally blown, the cooling system encircles the cylinder more than on older design engines.

Either have a compression or leakdown test done or do it yourself. That should determine if you have a blown headgasket or not, You can buy the tools to do a compression test for less than having it done.

You'll need a compression tester with a screw in hose(because the spark plugs are recessed into the head) and a sparkplug socket, 3/8drive ratchet, and extension (about 6"). It makes sense to buy a set that has all of this.

Pull all the plugs(on some engines the coil pack is in the way on the back but it only takes 3 small bolts to take off), install the tester in a spark plug hole and crank the engine. Watch the first compression stroke and record that. The compression will creep up as you keep cranking so the first stroke is more definitive for diagnosing. Do all 8 cylinders. If one or more have low compression the head gasket is leaking. (It could be a valve, head, or piston problem but then it wouldn't be running well)

A leakdown test is even better because it can pinpoint the leak better but you need a tester and air compressor so it costs more. I think from your symptoms the compression test is sufficient.

11-10-03, 12:50 PM
If we have a section for tech pictures I could put some up os a bad head gasket and the top of the block showing the coolant passages.

11-10-03, 04:34 PM
Zonie, it's the inconsitency of the leak. It'll leak sometimes when the motor's warm and running hard, but will hold it under normal driving. Then it held under hard driving, and normal driving, and held it when sitting idling. Then when the motor was cold, and the cap removed, it finally leaked it all out. Then it continued to leak it out as I refilled, then it held the water again. The car won't hardly do the same thing in the same situation. But, I am probably going to ask my buddy if he'll let me borrow the gear for a compression test from work. I can't afford to take it to a shop though. So, I will learn this motor more and more. I need to get a manual for this damn car.

11-10-03, 04:37 PM
I think I follow your question now with the antifreeze spraying everywhere. The system should not have air in it with the exception of the pressurized overflow tank. There should be an air gap in here to allow for the expansion of the fluid when hot. The limit of the cooling system is when the fluid is hot enough to expand to fill the entire overflow tank PLUS 15 or so psi held by the cap. The pressure is key as increased pressure of a fluid raises it's boiling point by a certain amount. The cap is calibrated to release pressure after this point out of that hose to prevent component failure from abnormally high pressure in the system. This commonly occurs from overfilling the tank or blown head gaskets. While overfilling the tank is pretty self explanatory and usually self corrected, head gaskets are a little more tricky. What hapens is combustion chamber GASES force themselves into the cooling system, where they become trapped. When a pocket of air is stuck in one of the many passages in the system, it is taking up space where there once was fluid. This fluid gets displaced into the overflow tank, resulting in a situation similar to an over filed tank. BUT the gases are not pressurized by expansion as the fluid is, they get thier pressure from the compression stroke in the engine. The system remains under pressure even when cold PLUS there is an abnormally high level of fluid in the expansion tank. When you opened the cap, the air pocket expanded forcing the fluid out of the tank and all over the place. Hope this answers your question! (especially for all that typing and thinking and stuff :) )

11-10-03, 05:10 PM
It's inconsistent because it is something that is breaking! It is not a calibrated spring or a switch or anything like that. :banghead:

Do the compression test and let us know what you find.

11-11-03, 02:49 AM
This forum kicks butt!

11-11-03, 04:16 PM
And your just now figuring this out...... :D

You've missed some mighty fine conversations..... Goto the POST YOUR PICTURE HERE THREAD in the lounge and all will be revealed!!! You might even post your picture there to!!!!

Sorry ShadowLvr for getting off topic..... let us know how this stuff works... I hope you can figure it out, its kinda confusing!!! :bonkers:

11-14-03, 05:44 PM
It can't be a head gasket, the coolant's just leaving the resevoir with the motor on or off. At this point she won't keep the coolant at all. Hoses underneath the resevoir?

11-14-03, 10:32 PM
I'm not just trying to give you a hard time but you have to start testing things. I'm doing a head gasket replacement on my brother's SLS now and his symptoms were similar and he kept thinking it was something else until he did the compression test.
Please do the compression test.

11-15-03, 01:27 AM
Here's a link to a picture of the block with the head off.


If you look at the pics on this link you'll see the coolant passages totally surround the cylinders. This is why you don't see water in the oil until the gasket is really blown. The oil drain passages are the three oval ones at the bottom of the deck.
He says the timeserts were a waste of time but we found 6 bad holes!!!! we didn't actually check all of them. With that many bad we had to timesert all of them and checking each was a waste of time.

11-15-03, 07:50 AM
Thursday she gets compression tested. I'm just hating having to go to a dealership for that, because I, and none of my friends, have the tools for a compression test.

11-15-03, 09:08 AM
Autozone will probably have the stuff you need to do it! And cheaper than the dealership......

11-15-03, 09:52 AM
I would encourage you to buy the tools and learn to do some things yourself.
You have your occupation as a student, here's an extra credit class!

You can buy the tools for less than an hour of dealer time. Sears has tool sets on sale this weekend! Compression tester is about $20.

11-15-03, 09:59 AM
If you reconsider and do it yourself (or with friends) let us know...I will give you a little more info if you feel you need it.

11-16-03, 10:50 AM
Oh really?!? I thought the compression testers were kinda pricey. If Sears sells them, I'm in good shape. Have a Sears Card, so get a discount as well. I think I'll call them, someone post on how to do a compression test please. :)

11-16-03, 12:48 PM
Read post 36 in this thread. I told you how to do it there.

11-16-03, 01:14 PM
Also get a small tube of antisieze compound for the plugs. It protects the threads in the head.
Get a tube so you can seal it and keep it, the little rip open packs make a mess if you keep them.

11-16-03, 01:16 PM
You'll need a compression tester with a screw in hose(because the spark plugs are recessed into the head) and a sparkplug socket, 3/8drive ratchet, and extension (about 6"). It makes sense to buy a set that has all of this.
I'd just like to emphasize this a little more. The screw in type are the best kind to get in ANY application, but they are a necissity on the Northstar. The other type is basically a cork that has a pressure gauge on it. You have to hold it in the spark plug hole while the engine is cranking. Not fun.

11-16-03, 01:44 PM
Thanks Dave,
The spark plugs are recessed in a N*. Get the compression tester that has an extension tube that screws in the hole, then the gauge itself locks on that tube.
That one should be somewhere between $20-30.

11-16-03, 01:48 PM
Another clarification. I might have made it sound like the compresion tester and the other tools would come in a set. The sockets and ratchet will be a set (make sure it has a spark plug socket) and the compression tester is seperate.

11-16-03, 01:58 PM
Arg!!! I have the tools, and I just lost the head for the spark plug. Plug 8 is locked on there so tightly I can't free it, and it's now got the head for my socket stuck on there, pulled from the bar.
Also, I created a chatroom in AiM called Phils Repairs Feel free to join it and make fun of me. :) Fin' plug is in there tight! My lugs were easier to free. Hey..... I wonder if I can get that kind of leverage......

11-16-03, 02:06 PM
The back is a real pain and you can lose stuff if it falls, I hate to make this too complicated but you're gonna have to jack up the car if you can't find it. If the plugs havn't been out before they get corroded in. That's why I recommended the antisieze.
After you find the socket tap the ratchet with a hammer. Hold the extension steady while you do that. I prefer to use light taps with a heavy hammer.

11-16-03, 02:08 PM
Where's that chat room?

11-16-03, 02:10 PM
I think I misunderstood. The socket is stuck on the plug?
try setting the ratchet to tighten and tap the handle to loosen. It may be slipping and angling on the plug.

11-16-03, 02:12 PM
AOL Instant Message, if you have it, my AiM name is ShadowLvr400 And cylinder 8 is the front driver side, easily accessed. The damn head is stuck on the plug now, in the hole. And don't know that I have any anti seize around here... Think WD 40 would work?...

11-16-03, 02:20 PM
To loosen, yes it might help. I highly recommend the antisieze before you replace the plugs.

11-16-03, 02:27 PM
I don't use AOL. Can I get into AIM with a Yahoo instant message ID?

11-16-03, 02:34 PM
nope, but I have Yahoo messenger as well Shadowlvr400 there too. I've now made a room in yahoo, Phils Repairs
And WD 40 rules!!!! Got plug 8 loosened and free!

11-16-03, 03:10 PM
Ok, front set of plugs free, out, and a bit oily...
Now, how am I going to get the rears out? Pull the coil packs and the sway bar?
Oh, can I test the front back, with the back bank still with the plugs in? (The wires have been pulled, so they won't fire)

11-16-03, 03:34 PM
You could do 4x4 but it's easier on the starter to pull them all.
Yes, pull the coil pack. It's 3 bolts.

11-16-03, 03:45 PM
Front bank Cylinder 8, 120 psi Cylinder 6 140 psi, Cylinder 4 140 psi, Cylinder 2 75 psi...... Going to work on freeing the back bank shortly. I will retest shortly, after pulling everything else, and making sure I had the final one plugged in properly... But that kind of drop is pretty indicative of a head gasket, isn't it? If so, She'll sit while I save up money, and I'll get those performance heads from XMS. And try to do a changeout myself.

11-16-03, 04:47 PM
Rear bank, 1-130 psi, 3-90 psi, 5-120 psi, 7-130 psi

11-16-03, 05:32 PM
Oh well. Look at it as an oppurtunity to install the timeserts, install some copper headgaskets, and then crank up the nawws. :yup: What do the XMS heads have done to them? Port and polish? Larger valves?

11-16-03, 09:53 PM
Yeah, you got 2 cylinders that are really low.... Start saving money!!

04-23-05, 06:49 PM
Thanks for the great thread. I think my 94 STS with *gasp* 91K is having this problem... disappearing coolant with no leak.


04-29-05, 09:01 PM
well after reading every post in this thread, I now know what I have to test for, but I think I already know what the answer will be...HEAD GASKETS
I am blowing water out of the coolant tank at high speeds and high revs. also it is overheating.
I will do the compression test now.