Overheating over 60mph

Mitch3 · #1 (**permalink**) 07-02-09, 01:09 PM

Well I'm still driving my '98 Eldo with just the usual upkeep expenses. More serious problem just recently started. I drive around town on a daily basis with a little highway. Average speed around here is 55mph. Car runs great. I still have to add coolant every month or so but don't get the low coolant message. Mechanics have checked for leaks, pressure checked, etc. No problems found. OK so here's the problem. About two months ago I took a run up I-87 with speed between 65 and 75. Stopped at a rest area and when I left I floored it to get back onto the thruway in heavy traffic. The temp guage started to rise to the 1 o'clock position then to the 2 o'clock position. I slowed down to 60 and temp started to drop. Slowed to 55 and it dropped to normal 12 o'clock. Stopped at a gas station and had to add about two or three quarts of coolant. Everything was fine after that. Yesterday, 2 months later, exact same thing happened. Never overheats around town. Oil is clean, no leaks found in coolant system. Could the thermostat be bad or are you going to say HeadGasket is going?

ppags · #2 (**permalink**) 07-02-09, 02:08 PM

Just dealing with the overheat, I would chalk that up to fluid flow. You were almost a gallon low, faster RPM, Faster flow, but not enough fluid in system to meet the demand. You need to stay on top of the level, check it more often, I would be suicidal if I let mine get that low, nevermind the fact you are nursing another problem.

submariner409 · #3 (**permalink**) 07-02-09, 02:37 PM

You need to let the system settle for a couple of days after adding coolant to halfway up in the surge tank, COLD. Then, get to a GOOD radiator shop and have them test the airspace over the coolant in the surge tank for the presence of exhaust gasses.

Cross your fingers, caress your credit card, call Jake the stud man (^^^ banner ad), and cross your fingers again. Not good symptoms.

A properly operating Northstar cooling system will NEVER - NEVER need to be "topped up".

00 Deville · #4 (**permalink**) 07-02-09, 04:18 PM

Quote:

Originally Posted by submariner409

You need to let the system settle for a couple of days after adding coolant to halfway up in the surge tank, COLD. Then, get to a GOOD radiator shop and have them test the airspace over the coolant in the surge tank for the presence of exhaust gasses.

NAPA has the Exhaust gas test kit it will run you about $50

Talamant3z · #5 (**permalink**) 07-02-09, 04:56 PM

Quote:

Originally Posted by 00 Deville

NAPA has the Exhaust gas test kit it will run you about $50

or u can go to autozone and use it as a loaner tool for free

**Ranger** · #6 (**permalink**) 07-02-09, 05:30 PM

Hate to say it Mitch, but it doesn't sound good. Follow Subs advice.

Mitch3 · #7 (**permalink**) 07-02-09, 08:11 PM

Well today the outside temp is hovering around 68 degrees so figured I would have some fun. I drove around town for about twenty minutes, in and out of traffic to make sure temp was up there. No overheat. Got on the highway and did a couple of WOT's to simulate what I did on those two overheat situations. Then I continued on the highway at 70 mph for about five minutes. No overheat. Got home. Checked the coolant level and all was OK. The first time I had the overheat problem, the outside temp was hovering over 90 degrees. Second time it was around 85 degrees. Guess I'm safe as long as I don't go on any long trips in hot weather. ???????

Talamant3z · #8 (**permalink**) 07-02-09, 09:11 PM

Quote:

Originally Posted by Mitch3

Well today the outside temp is hovering around 68 degrees so figured I would have some fun. I drove around town for about twenty minutes, in and out of traffic to make sure temp was up there. No overheat. Got on the highway and did a couple of WOT's to simulate what I did on those two overheat situations. Then I continued on the highway at 70 mph for about five minutes. No overheat. Got home. Checked the coolant level and all was OK. The first time I had the overheat problem, the outside temp was hovering over 90 degrees. Second time it was around 85 degrees. Guess I'm safe as long as I don't go on any long trips in hot weather. ???????

WHAT! 68 man your lucky

**Ranger** · #9 (**permalink**) 07-02-09, 09:37 PM

Mitch, outside temperature should make no difference. The engine was tested in death valley. IF it is a head gasket it will slowly get worse. I'd test it.

submariner409 · #10 (**permalink**) 07-03-09, 12:25 AM

Whether the ambient air temperature is 20 or 100 degrees the engine should run in the thermostat/fan operation band: 188 to 224 degrees, 20 mph or 120 mph.

As Ranger posted, these things have very healthy cooling systems. IF you are continually adding coolant to keep the level at halfway up the surge tank, COLD, then you have one of two problems: A system leak or failing head gasket(s).

If you cannot positively document a leak, then test the airspace in the surge tank for exhaust gas.

Raze · #11 (**permalink**) 07-03-09, 09:20 PM

Mitch, do you have the plastic connector piece between your front bumper and your radiator support or if when your hood is up can you look and see the ground between your radiator support and your front plastic bumper?

I second getting the $50 block tester, it'll tell you in 10 minutes if you have a big problem or not.

Also, did you recently do any coolant system work and properly bleed the system? I know our system is 'supposed' to be self-bleeding but trust me, it does not always work, I recently re-bled my system after moving a hose to get to the alternator after I didn't bother at first and guess what, I got some bubbles out of the system, which again is 'supposed' to be self-bleeding. I find it funny there's a bleeding system procedure in the FSMs as well for my 98 Eldo...

Goodluck...

Talamant3z · #12 (**permalink**) 07-04-09, 12:53 AM

Quote:

Originally Posted by Raze

Mitch, do you have the plastic connector piece between your front bumper and your radiator support or if when your hood is up can you look and see the ground between your radiator support and your front plastic bumper?

I second getting the $50 block tester, it'll tell you in 10 minutes if you have a big problem or not.

Also, did you recently do any coolant system work and properly bleed the system? I know our system is 'supposed' to be self-bleeding but trust me, it does not always work, I recently re-bled my system after moving a hose to get to the alternator after I didn't bother at first and guess what, I got some bubbles out of the system, which again is 'supposed' to be self-bleeding. I find it funny there's a bleeding system procedure in the FSMs as well for my 98 Eldo...

Goodluck...

how do you bleed the system?

**Playdrv4me** · #13 (**permalink**) 07-04-09, 05:25 AM

To the OP... you are having CLASSIC early headgasket failure symptoms. You need to follow Ranger and Sub's advice or you'll just end up finding out the hard way later.

jeffrsmith · #14 (**permalink**) 07-04-09, 11:08 AM

Quote:

Originally Posted by Playdrv4me

To the OP... you are having CLASSIC early headgasket failure symptoms. You need to follow Ranger and Sub's advice or you'll just end up finding out the hard way later.

I'll second that. When I first bought mine I wasn't aware of the HG problems. For the first three months of ownership the car ran fine, apart from having to add coolant on a regular basis, also noting that when I would open the fill cap there always seemed to be pressure. Then the car overheated on me, once. I tested for combustion gases in the coolant reservoir and guess what. I continued to drive it for another month and had no further instance of overheating or need to add coolant. When I pulled it apart the gaskets were shot. Good luck!

Mitch3 · #15 (**permalink**) 07-04-09, 12:53 PM

My garage is closed 'til Tuesday so I'll have him pull an exhaust gas test next week and hope for the best. Stupidly, I never pulled the codes when I had the overheat problem. Checked this morning and I have one current, P1483, which is coolant system performance. Did a search here and a couple of comments on this code say it relates to the radiator fan not working. Took it for a 15 mile hard drive and checked the fans. One was running the other wasn't but I guess that's normal unless the engine is really hot. Could this be any way related to the overheat???