: N* Coolant Tough To Fill

04-25-07, 11:47 AM
this forum has helped me understand the toughnes of the N* engine.

I use the TABS, replaced WP, Thermo, Hoses , UNSTOPPED the sm air bleed line to Surge Tank. repl Presure CAP. 1994 Concours 4.6L , 175 K mi.

I just had another incident and suspect that mechanic did not get a complete Coolant FILL and or did not burp the baby.

I brought tabs, coolant mixture and distilled water. He installed . I Drove it two short 2 mi trips and then hooked up 16' SCAMP trailer (very light).

Drove 16 miles W of St.louis up significant grade and into ENG COOLANT HOT, situation. Stopped added nearly 2 gallons water. Waited 40 minutes headed back to town . Overheated second time. Added water. Waited 30 minutes. Back home unhooked trailer. Refilled coolant . Went right back out WITHOUT trailer, same route drove it hard . Never Overheated. So I am thinking eng is O K , Thermo is O K no leaks, no boiling , Fans O.K. , WP Idler was checked year ago however i think it is Original.

Question how can I get the right QUANTITY of coolant installed for sure?
mechanics state that it will not hold w specs call out. That makes me thing I was drving w a lot of air and cavatation issues.

I have no thermostat gage so overheat is always a surprise.

Any suggestions would be appreciated. I think the engine is sound , it runs great.


04-25-07, 07:12 PM
Your owners manual will tell you exact capacities, but it should be 2 inches below the top of the tank. Its possible the extra weight of the trailer is just exaggerating a problem. The coolant has to be going somewhere, it just doesn't disappear. Look everywhere you can for leaks, after you make sure its at the exact level. Especially since you just had alot of work, its possible someone didn't tighten a clamp or bolt somewhere. Also do a search for "headgasket" on the forum, you should find about a million posts that tell you how to diagnose a blown headgasket. Its always better to expect the worst and hope for the best. Keep us updated. my northstar ran perfectly with no loss of power before it hit 265 degrees and shot coolant out the overflow.

04-25-07, 09:42 PM
The "right quantity of coolant" is simply 2" below the filler neck.

I just had another incident and suspect that mechanic did not get a complete Coolant FILL and or did not burp the baby.
If the purge line is clear, it will "burp" itself. Maybe he did not run the RPM's up to purge any air in the system after the refill.
Not sure what you mean by "mechanics state that it will not hold w specs call out".

04-25-07, 11:10 PM

I bring the coolant , distilled water and parts plus the owners manual w spec for coolant volume.

Once they drain system they state cannot get all the quantity of product installed.

Thank you for taking a look.

04-25-07, 11:16 PM
That is because you can never drain the cooling system completely, so you will never be able to put the "advertised" capacity back in. As long as the level is 2' below the neck and stays there, you are fine.

04-27-07, 08:40 AM
pull the air purge line off and check the nipple with a very small screwdriver or somesuch to poke through it.. if that is plugged you'll have hell trying to fill that engine.. and and hotspots will make air accumulate in the block..

you can get a "block tester" at any local autoparts store and diagnose your head-gasket really quick.. that way you skip all the other "testing" people recommend.. and the headaches of uncertainty that go with it.

04-28-07, 11:27 AM
Thank you for the insights and practical knowledge.

Fill level is 2" below the top and STAYS there is a lot better than to try and measure what is drained and installed. Ranger I am going to write your advise on a post It Stick note and place it in Owner's Manual on page that states 12.5 qt coolant capacity.

Traunt, your post was an eye opener. I did have a plugged bleeder line once and it was supposely cleared w compressed shop air. I have removed that line (COLD) at the surge tank recently to confirm a positive flow. Your TIP to clear the little plastic nipple adds a new dimension.. There could be a possibilty of the line being checked as positive flow and clear YET the little nipple being stopped up! Now I finally know to check the bleeder line AND the surge tank nipple.

Thank you


05-03-07, 10:53 AM
Burping system is extr important. I have seen a 10 degree temp spread as a result of being 1 qt low on anti freeze.