Strange coolant issue

[AutoVation]

Did a coolant change today.

I drained the coolant and less than a gallon came out. That had me really worried. So I go to fill it up and it will only take less than a gallon until the radiator is fill. So I run the engine to try to get the thermostat to open and make the radiator level drop. Problem is... it never drops. The temp gage always reads on the low side so I'm not sure what is going on.

Anyone have this issue before?

The heater core had also been replaced just before I purchased the truck (less than 10k miles ago). There has always been a faint smell of coolant but I thought that was somehow from extra coolant left over from the heater core job.

At least the oil change didn't have any issues!

 

[NJ93TY]

Re: Strange coolant issue

How long are you letting it run for? And do you have the heat on when your run it to burp it?

 

[WyoSyclone]

Re: Strange coolant issue

I tried doing a coolant change and had the same luck... I took my Sy to our local Cadillac dealer early on a Saturday morning and had them put it on their coolant flushing machine.. they actually take one coolant line loose from the radiator and hook the entire system up in series to the flushing machine..... the engine is started and warmed up with the machine continually cleaning/flushing the system. I had them leave it on the Sy for about 20minutes with it idling... cleaned it up great, plus their method makes sure you don't get any air pockets trapped in the system.

 

[AutoVation]

Re: Strange coolant issue

How long are you letting it run for? And do you have the heat on when your run it to burp it?

it idled for at least 20 min. i drove it also, no difference.

 

[AutoVation]

Re: Strange coolant issue

I tried doing a coolant change and had the same luck... I took my Sy to our local Cadillac dealer early on a Saturday morning and had them put it on their coolant flushing machine.. they actually take one coolant line loose from the radiator and hook the entire system up in series to the flushing machine..... the engine is started and warmed up with the machine continually cleaning/flushing the system. I had them leave it on the Sy for about 20minutes with it idling... cleaned it up great, plus their method makes sure you don't get any air pockets trapped in the system.

I did notice that the upper coolant hose (coming off the top of the radiator) did not seem to be pressurized. Is it supposed to?

 

[WyoSyclone]

Re: Strange coolant issue

I did notice that the upper coolant hose (coming off the top of the radiator) did not seem to be pressurized. Is it supposed to?

You'll have the pressure from the coolant system itself.... main thing is it should be quite hot once the thermo opens.

 

[AutoVation]

Re: Strange coolant issue

You'll have the pressure from the coolant system itself.... main thing is it should be quite hot once the thermo opens.

It wasn't hot either. Does it sound like my coolant is trapped in the engine? Doesn't make sense as it's running cool (according to the inaccurate stock gauge).

 

[WyoSyclone]

Re: Strange coolant issue

It wasn't hot either. Does it sound like my coolant is trapped in the engine? Doesn't make sense as it's running cool (according to the inaccurate stock gauge).

The stock temp gauges are best used for cooking turkeys.. they have no place on a Sy or Ty

Now's the time to replace your thermo. Get it changed, let the truck run, get good and warmed up, and make sure the thermo is opening. Do you have any type of scan software (DataMaster/TunerPro) that you can use to verify the real coolant temp?

 

[AutoVation]

Re: Strange coolant issue

The stock temp gauges are best used for cooking turkeys.. they have no place on a Sy or Ty

Now's the time to replace your thermo. Get it changed, let the truck run, get good and warmed up, and make sure the thermo is opening. Do you have any type of scan software (DataMaster/TunerPro) that you can use to verify the real coolant temp?

I've got the cable but no software. Where can I pick up the software?

Also, is there a vacuum line diagram somewhere? I've tried a search but keep coming up with a diconnected link. I think I have a disconnected line somewhere because 2 speeds on my A/C aren't working anymore.

 

[oboym]

Re: Strange coolant issue

Drilling an 1/8" hole in the body of the thermostat will allow you to fill the system without the above hassle of bleeding. Still takes awhile to fill, but at least you can get enough coolant in the system to get the thermostat to open, so you can finish filling. Good idea for those that work on their engines frequently. The 1/8" hole won't affect thermostat performance, or heater output under most conditions.

DaveP

X2 :tup:

 

[sy#2921]

Re: Strange coolant issue

Dave, don't most newer thermostats have a small bypass hole built in these days for that reason? Since thermostats are so cheap might want to recommend just swapping for a newer one.

 

[sly dvl]

Re: Strange coolant issue

Easy check. Open your rad cap (engine cold and not running) and then start your truck. If you see flow right away (you may need to rev it a little if the rad is full full full) then you either have no thermostat or a thermostat that is stuck open.
Because your gauge always reads low I suspect you need a stat. Like Dave mentioned, drain the coolant, remove a heater hose to allow air to enter the system for draining and then remove the thermostat. When refilling, leave the heater hose off and the thermostat housing off. Fill the coolant until it shows up in the thermostat cavity and all the air is out. Reassemble with new stat and then continue to fill until it shows up at the heater hose. Install heater hose and then fill to completion.
Replace cap and fill reservoir. You may also need a new rad cap if the system wasn't building any pressure, but I suspect it just wasn't getting hot enough to build pressure.

 

[Tooky]

Re: Strange coolant issue

FYI just draining the petcock on the radiator doesn't change much coolant, as you found out. There are 2 block drains, one on each side of the block. The driver's side one has proved impossible to access on my truck (even with the exhaust manifolds removed I could not budge it), the passenger's one is a lot easier and located right near the starter.

 

[fivetodrive]

Re: Strange coolant issue

I have debated cutting the upper hose and installing one of the moroso radiator hose fillers...

But the problem seems to be securing it...

 

[Tooky]

Re: Strange coolant issue

Hey Dave, on the topic of coolant flushes, when you do all that (I like your flush idea), what do you do with the drained water/coolant mixture? Assuming you flush it over and over until it's clear, you'll have many gallons of water to clean up afterwards. I have pets so I have to be careful with that stuff and also have a well so I cant just dump it in the backyard or I'll end up drinking it..

 

[sly dvl]

Re: Strange coolant issue

Hey Dave, on the topic of coolant flushes, when you do all that (I like your flush idea), what do you do with the drained water/coolant mixture? Assuming you flush it over and over until it's clear, you'll have many gallons of water to clean up afterwards. I have pets so I have to be careful with that stuff and also have a well so I cant just dump it in the backyard or I'll end up drinking it..

Yes I'm curious Dave. What do you do with all that contaminated H2O? :rotf: j/k