Overheating In January

[Red Box Rebel]

Never had an overheating problem with the '97 Mark VIII until now. The system has been drained and a new thermostat has been installed. All new hoses and a good 50/50 mix of new coolant and clean water has been installed. All air has been purged from the system and the heater core has been checked for any blockages and there were none.

The radiator has not been be checked for blockages, but appears to be free from obstructions and junk. The flow through the system appears to be normal, but I am not completely sure.

The engine runs at normal operating temps for 15 to 20 minutes and then starts to overheat after being driven over 35 MPH. The cooling fan is coming on and is blowing high.

I do have a broken blend door actuator, but I do not see how that would cause overheating in January with temps in 30s.

Any suggestions would be most welcome.

Thank you and Happy New year.

 

[Roadboss]

Re-burp the system.

 

[tixer]

+1 I'd say you almost certainly have an air bubble in the crossover tube by the alternator. Remove the crossover cap, top off, run and repeat. I've hard of some people having to do this multiple times before truly clearing the system of air.

I suppose it is also possible that you have a defective thermostat. I have encountered that myself. Years ago, Dad taught me to test them by boiling it in water on the stove. (using Mom's best saucepan, of course..)

 

[Red Box Rebel]

Thanks for the replies and suggestions, but 99.999% sure that there is no air in the system.

Any other suggestions?

 

[tixer]

Did you get the cap off on yours? I noticed another post where you were looking for a new crossover tube.

Mike (beerdog) told me he managed to get one off using a pipewrench before. I've also heard of welding a nut to the cap. I was one of the lucky ones. I was able to oh-so-gently tap mine off with a 1/4" socket wrench in the usual manner. I replaced it immediately with Jay's super-high-tech improved version. (more info here: http://www.lincolnsofdistinction.org/vbulletin/showthread.php?t=31179)

I'm afraid I really cannot think of much else to look for..

 

[LSC HUNTER]

99.99% is not good enough for these cars.

Driller has even gone as far as a funnel that fits into the crossover tube so you can fill it beyond and let it keep running for an extended period so that you KNOW for sure that there is no air in the system.

99.99% of the time after coolant system work it is air. Now if you did not do the work as a preventitive measure and it was done because of an over heating problem then it is something else. Not sure from your original post what the order of operations was.

 

[Red Box Rebel]

The system was overheatig before I performed the hose and thermostat replacement. The filler cap on the crossover pipe will not turn and cannot be removed.

The thermostat was bad and the coolant was very old and needed to be replaced. I was able to put two gallons of new coolant and two gallons of clean water in the sysytem. I do not believe there is any air in the system, but I cannot remove the cap to actually see.

All new hoses and coolant and a new thermostat have been installed.

 

[DLF]

If you can't get the cap off, then you can't properly purge the cooling system.

 

[PenGun]

Big Vise Grips and smack them with a hammer, just tap it at first then harder till it comes.

 

[beerdog]

A pipe wrench with nice sharp teeth works well. Just look closely as you do it to ensure you catch just just the cap. Many people have done it. I though both of ours were stuck for good and was afraid to use a pipe wrench untill I saw Jeremi do it. Spray it down good with PB or some other penetrating oil. You will be suprised how rusty it can get in side there.

 

[Meister]

Thanks for the replies and suggestions, but 99.999% sure that there is no air in the system.

The filler cap on the crossover pipe will not turn and cannot be removed

Aye, there's the rub! You absolutely have air in your system. The ONLY way to get the air out is to purge it from the highest point in the cooling system (the cross-over pipe cap), and properly burp it.

I'd stop driving the car until that is done. You are risking permanent damage by running it hot.....

Doug

 

[driller]

I agree, if the system was not filled via the crossover tube because of a frozen cap, it is highly likely there is air still trapped.

Google "Lisle funnel" and you will find the funnel kit I use and believe in. It allows you to run the system with a charge of coolant in the funnel while allowing air to be purged without making a complete mess. Once the system is up to operating temperature and warm coolant is circulating through the heater coil, you simply drop in the tee handle plug in the funnel, remove the funnel with coolant still in it and replace the cap.

Further, the car should be allowed to completely cool (overnight is preferable) and the system checked when cold by removing the cap at the crossover tube BEFORE removing the reservoir cap. Top off the crossover tube with coolant if necessary and replace the cap. THEN remove the reservoir cap and fill the coolant reservoir to the cold fill level. REPEAT as necessary until the crossover tube is completely full when checked and the coolant reservoir is properly full to the cold fill level and no further coolant is required to be added. Only then are you 100% sure there is no trapped air in the coolant system.

If you simply top off the coolant in the reservoir without removing the cap at the crossover tube and checking, there may still be trapped air in the coolant system!

Bottom line is, if you cannot remove the cap at the crossover tube, you are not going to know if there is air trapped in the coolant system or not.

 

[LSC HUNTER]

See we do get to the heart of the problem.

Hope you get the cap off or a replacement crossover. I went to do this to my 97 and found that someone previous had broken a 1/4 ratchet in the cap and I could not get anything in there to try myself so I did the vise grip trick with PB. Tapped the plug with a hammer around the edge before I tried to apply or turn the vise grips. Came right off. Patience is the key here and if you try to rush you will create more frustration.

Keep us informed as to how it goes.

 

[95blklsc]

Another option for getting the cap off that I have used is take a dremel with a cut off wheel and slice off two tabs from the edges of the cap. This will give a big pair of channel locks, adjustable wrench etc a better spot to grip. Once you do get it off be sure to use some antisieze on it. There was a guy selling new caps with a hex nut on the top, might be something you think about getting to replace yours with once you get it off.

 

[Lvnmarks]

There was a guy selling new caps with a hex nut on the top, might be something you think about getting to replace yours with once you get it off.

I was wanting to get one of those if he ever makes more, I forgot who it was though.

 

[Roadboss]

Go to your local dealer and get a replacement cap. Then stop and get a big easy out at your local parts store, and a two handle tap wrench if you don't have one along with a can of penetrating fluid. When you get home drill the top of the cap deep enough, but do not break thru the bottom of the cap (chips into coolant), and a big enough drill so your easy out can get a good bite. Be sure you get the penetrating lube on and soaking (tap the cap some to help it penetrate). Then have at it with your easy out and t handle tap wrench. I'd even give the top of the tool with a whack to help it bite in.

This is just a suggestion of another method of removal. By now you know that the cap has to be removed or you will never fix your problem. New caps are only $8.00 each., and I always use di-electric grease installing them.

 

[Red Box Rebel]

Okay Guys!! Thank you all for the great advice.

I have managed to remove the crossover cap, but air in the system was not the problem. I discovered a slight leak in the coolant recovery tank. It was not noticeable at first until it became more than just a slight leak.

Once the tank is replaced, I will go through the proper re-fill procedure. Hopefully there will be no mare overheating problems.

 

[Meister]

Okay Guys!! Thank you all for the great advice.

I have managed to remove the crossover cap, but air in the system was not the problem. I discovered a slight leak in the coolant recovery tank. It was not noticeable at first until it became more than just a slight leak.

Once the tank is replaced, I will go through the proper re-fill procedure. Hopefully there will be no mare overheating problems.

Glad to hear you got it off. The coolant recovery tank may have been a secondary leak, but I guarantee that you had air in the system if you never had the cap off before.

Doug

 

[beerdog]

How did you get it off?

 

[Red Box Rebel]

How did you get it off?

I got the cap off with a pair of small vice grips and a hammer. Once I was able to get a good grip on the edge of the cap, I tapped the vice grips and the cap slowly came loose.