[cmpcpro]

Hey guys, I’m trying to stick with this car, I love these cars, and this is a one owner 100k mike car from an old lady but it’s sure testing me.. today I decided to dump it but now really want to keep it.. so today I was driving up my hill and I noticed my temp gauge went up a bit and then back down... it’s never done that before... then I noticed check coolant level.. unfortunately I couldn’t stop because of where I was I had to go a good couple miles... once the temp gauge started getting towards 3/4 I pulled into the dirt in a dangerous place but shut it down before it hit 3/4... when I checked under the hood I blew a rubber plug on the passenger side of the radiator... it died from old age.. I had someone come for me and went to the parts store to get another rubber cap and some coolant/water.. It took 2 gallons and now has been fine but I am curious:

What temperature was it at right before 3/4? The fans weren’t blasting and when I popped the hood it wasn’t barreling heat off it or anything, the engine felt normal.. also, what is the capacity of the coolant? I’m taking it I was 2/3’s down on coolant, if it does indeed take 12.5 quarts.. is that including the heater core meaning I only had one gallon of coolant in the entire system??

Thanks for the answers guys! Trying to hang in here!

 

[ELDORADO2K]

What temperature was it at right before 3/4?

240 degrees.

In my 97’ Seville I’ve lost the coolant on 2 occasions.
Once when my water pump belt chewed up the pulley. I pulled over and shut the car off right before the gauge was about to hit the red.

Another time the upper radiator hose ruptured while I was driving and I decided I was close enough and limped home and shut the car off moments after it hit the red.

It survived both those close calls without any issues. The redline is 260 degrees.

 

[cmpcpro]

240 degrees.

In my 97’ Seville I’ve lost the coolant on 2 occasions.
Once when my water pump belt chewed up the pulley. I pulled over and shut the car off right before the gauge was about to hit the red.

Another time the upper radiator hose ruptured while I was driving and I decided I was close enough and limped home and shut the car off moments after it hit the red.

It survived both those close calls without any issues. The redline is 260 degrees.

Thanks, I've also just read about camel mode and have a whole new respect for these Northstars.. they will go into Camel Mode at 270deg and you can drive them up to 100 miles without coolant, they run on one bank at a time and suck air into the other bank turning the motor into an air cooled motor... that is awesome!

One thing I am still curious about, what is the true capacity of the cooling system? When they say 12.5 quarts is that when draining the coolant or when the whole system is bone dry? I am asking because I am curious if its taking the heater core into account.. I know on my diesel truck they have capacities listed all over but in the shop manuals there are different capacities for when its bone dry or has been rebuilt..

I was through with this car today lol, I have 6 vehicles and I was going to pull everything out of this one and put it into my S55 AMG benz but I went for a ride in her tonight and remembered why I bought another one of these cars!

 

[Harry Yarnell]

Rubber plug?

 

[Submariner409]

Rubber plug - he may have an older water-cooled alternator radiator installed. The passenger side tank rubber plug nippl-e would connect to the alternator coolant discharge hose. The system was discontinued due to lack of need and constant leak problems.

12.5 to 14 quarts, bone dry. Sometimes quite a bit of fun to get all the air bubbles/blockage out of a total refill. Make very sure the colantpurge line is clear and flows coolant at idle - that's the hose that removes bubbles from the main system and dumps the air/gas into the surge tank.

All these FWD cars use the same coolant temp sender (ECT) so the tick marks on either the large or small gauge - and most of the digital gauge bars - read the same values.

Posted throughout the Northstar FWD forums for years ....... read the fine print.

 

[cmpcpro]

12.5 to 14 quarts, bone dry. Sometimes quite a bit of fun to get all the air bubbles/blockage out of a total refill. Make very sure the colantpurge line is clear and flows coolant at idle - that's the hose that removes bubbles from the main system and dumps the air/gas into the surge tank.

All these FWD cars use the same coolant temp sender (ECT) so the tick marks on either the large or small gauge - and most of the digital gauge bars - read the same values.

Posted throughout the Northstar FWD forums for years ....... read the fine print.

Thanks, I had the AC on and I didn’t hear the fans kick on high and I shut it down before it got to the 240 3/4 mark, so it probably only made it to about 230 or so... what amazes me is while I was losing coolant the system was fighting to keep it cool, the needle would climb and then drop back down a bit until I lost most of the coolant and then obviously it couldn’t help it, but running on one out of three gallons of coolant and still holding it’s own is pretty impressive... I will check that hose tomorrow and make sure it’s flowing, if it’s not what stops it from flowing?

Thanks again!

 

[cmpcpro]

Rubber plug?

On the passenger side of the radiator there is a little inlet/outlet and mine has a rubber cap with a hose clamp on it. Probably not stock but I don’t know what went there or if it’s just an aftermarket radiator.

 

[ELDORADO2K]

Just to clarify, when I said “limped home” I didn’t mean Camel mode... I simply meant I eased that bad boy home as smooth and gently as possible. Bad choice of word on my part.

 

[Submariner409]

Yeah, that ^^

"Limp home" and "Camel mode" are, for all practical purposes, synonymous. Around the time of electronic ignitions and timing controls the term "limp home" referred to an ignition system failure default to a fixed timing BTDC - you limped home.

Camel Mode is further discussed in the Technical Archive .............https://www.cadillacforums.com/cadillac-tech.html ......... primarily about the pre-2000 Northstars/systems, written by a GM Northstar Powertrain Systems engineer, an old CF member from Day 1.

 

[Ranger]

On the passenger side of the radiator there is a little inlet/outlet and mine has a rubber cap with a hose clamp on it. Probably not stock but I don’t know what went there or if it’s just an aftermarket radiator.

I think those caps are for the oil cooler lines (if so equipped). Mainly just for shipping. No harm done if they are missing.

One thing I am still curious about, what is the true capacity of the cooling system? When they say 12.5 quarts is that when draining the coolant or when the whole system is bone dry?

With a drain and refill, you'll only get about 1 1/2 gallons out of it.

 

[cmpcpro]

On the passenger side of the radiator there is a little inlet/outlet and mine has a rubber cap with a hose clamp on it. Probably not stock but I don’t know what went there or if it’s just an aftermarket radiator.

I think those caps are for the oil cooler lines (if so equipped). Mainly just for shipping. No harm done if they are missing.

One thing I am still curious about, what is the true capacity of the cooling system? When they say 12.5 quarts is that when draining the coolant or when the whole system is bone dry?

With a drain and refill, you'll only get about 1 1/2 gallons out of it.

Thanks, but you must be mistaken on only getting a gallon and a half.. 12.5 quarts is over three gallons and the car took two gallons just to get back to normal.. the leak was about 1/3 up the radiator so that means there had to be about a third left of coolant at the least, which would make sense if the 12.5 is correct, I was just curious as to how much more the heater core took, but looking at the core it looks like it only holds a quart or two.

 

[Submariner409]

He's saying that the Northstar has no cylinder block coolant drains and that the entire heater circuit stays full - during a normal engine-off coolant change.

A leak anywhere in the cooling system of a running engine will usually pump/leak/blow off practically all the coolant in the system.

You must use a pressure/vacuum coolant machine to change ALL the coolant in a Northstar system.

The Northstar radiators for the cooled alternator have a nipple about 1/3 of the way up the rear side of the passenger side end tank. A short hose from the alternator case connects there. If there are caps on the front side of the passenger end tank the radiator is also equipped with an oil cooler heart exchanger - for those few cars with HD Cooling option V03 (totally unnecessary in any daily driver Northstar car - even at the track - unnecessary).

 

[Ranger]

Thanks, but you must be mistaken on only getting a gallon and a half..

Nope, I must have done it AT LEAST a half dozen times. I buy a gallon of coolant and a gallon of distilled water and always have close to a half gallon left.

If there are caps on the front side of the passenger end tank the radiator is also equipped with an oil cooler heart exchanger

Oops, I meant "oil" cooler. :bang2: Post #10 corrected.

 

[cmpcpro]

Thanks, but you must be mistaken on only getting a gallon and a half..

Nope, I must have done it AT LEAST a half dozen times. I buy a gallon of coolant and a gallon of distilled water and always have close to a half gallon left.

If there are caps on the front side of the passenger end tank the radiator is also equipped with an oil cooler heart exchanger

Oops, I meant "oil" cooler.

Post #10 corrected.

I got it, like sub said you meant draining and filling, which keeps the coolant in the engine and core.. but if you drain the whole thing it’s going to take more than that..

 

[cmpcpro]

He's saying that the Northstar has no cylinder block coolant drains and that the entire heater circuit stays full - during a normal engine-off coolant change.

A leak anywhere in the cooling system of a running engine will usually pump/leak/blow off practically all the coolant in the system.

You must use a pressure/vacuum coolant machine to change ALL the coolant in a Northstar system.

The Northstar radiators for the cooled alternator have a nipple about 1/3 of the way up the rear side of the passenger side end tank. A short hose from the alternator case connects there. If there are caps on the front side of the passenger end tank the radiator is also equipped with an oil cooler heart exchanger - for those few cars with HD Cooling option V03 (totally unnecessary in any daily driver Northstar car - even at the track - unnecessary).

Thanks, yeah my car is an 02 so no water cooled alt, but evidently they were still using the radiators and plugging them back then or it’s been replaced.. my rubber cap/plug was cracking from age so it pushed about 2/3’s of the coolant out by the time I could stop... I tried to get as far as possible to a safe place but was going to stop and keep the engine from hitting 3/4 no matter what and did so with just enough space to get the car in the dirt so traffic could keep going.. while I was under it fixing it I could feel it shake every time someone drove by... I was actively praying to God to keep me safe because I knew if someone hit that car I was gone!

 

[Ranger]

I got it, like sub said you meant draining and filling, which keeps the coolant in the engine and core.. but if you drain the whole thing it’s going to take more than that..

The point is, you CAN'T drain the whole thing.

Thanks, yeah my car is an 02 so no water cooled alt, but evidently they were still using the radiators and plugging them back then or it’s been replaced.. my rubber cap/plug was cracking from age so it pushed about 2/3’s of the coolant out by the time I could stop.

I can't imagine a radiator for a water cooled alternator being used on a car with a non water cooled alternator. Sounds like someone bought the wrong one and fabed up a plug. That said, I am not sure where the water cooled alternators sourced the coolant from. My guess would be NOT from the radiator, but I could well be wrong.

 

[Submariner409]

The w/c alternator coolant source was a small line much like the purge line.

I've often wondered why the system was altered like that. The thermostat blocks the lower radiator hose - the coolant return line - until the entire engine/heater/purge circuit temp rises and stabilizes to begin thermostat opening - 188 degrees. So, no coolant can flow through the alternator case until the engine is fully warmed up and the thermostat allows coolant to circulate through the radiator.

Look at this drawing of the water pump cover/thermostat housing. The thermostat blocks all radiator flow until the engine/heater/purge circuit is up to temp. The little wiggle pin "air bleed" won't allow the slightest tiny bit of flow because it seats toward the engine.​

 

[cmpcpro]

I got it, like sub said you meant draining and filling, which keeps the coolant in the engine and core.. but if you drain the whole thing it’s going to take more than that..

The point is, you CAN'T drain the whole thing.

Thanks, yeah my car is an 02 so no water cooled alt, but evidently they were still using the radiators and plugging them back then or it’s been replaced.. my rubber cap/plug was cracking from age so it pushed about 2/3’s of the coolant out by the time I could stop.

I can't imagine a radiator for a water cooled alternator being used on a car with a non water cooled alternator. Sounds like someone bought the wrong one and fabed up a plug. That said, I am not sure where the water cooled alternators sourced the coolant from. My guess would be NOT from the radiator, but I could well be wrong.

I hope that the case! That means I have a new radiator... as for the coolant, you can use an extractor to suck it out or like my car did on it’s own, use the water pump to pump it out!

 

[basscatt]

I hope that the case! That means I have a new radiator... as for the coolant, you can use an extractor to suck it out or like my car did on it’s own, use the water pump to pump it out!

============================

as for the coolant, you can use an extractor to suck it out
if you look at the configuration of the radiator -

there is no way to "suck it dry" -

you will see that there is simply no way to drain the cooling system completely dry either -

or like my car did on it’s own, use the water pump to pump it out!
can't happen -
once the coolant level gets down to the water pump level -
the water pump can't pump air -

as Ranger said - you can drain about half of the coolant out -
UNLESS you stand the car upright on its front bumper - and remove the radiator -

 

[cmpcpro]

What a great design! I haven’t checked the level of the water pump but I’m assuming it’s higher.. my system pumped out two gallons, and he’s saying it only takes 1.5 on a refill.. perhaps because the system is pressurized? It was pushing coolant out of a small crack on the exhaust side, so maybe not enough of a crack to loose too much pressure? What is stopping you from pulling a hose and sticking the extractors tube down there and sucking it up?