Overheating and slight rumble when driving over 55mph

Jay. Does it have a fan clutch?

If you search this group, for my posts about my

It orig started coming back to Texas from Florida. At around 5-55, I would get some stumbling and temp guage rising, but if I went faster, things would improve, or if I went slower.

I changed a number of things (plugs/wires/fuel filter) and the problem went away - it was only coincidence. About a month later, the problem cropped up again.

Turns out the cat was broken internally and pieces must have shifted around, "clearing up" the problem, then shifted around again and re-clogged.

Thanks for your input. The thing is that a new catalytic converter was just installed a few days ago so I dont think that's it unless some old buildup from the exhaust system has moved into the catalytic after installation. Any further input?

Jay

I'm not sure if it has a fan clutch.. but the fan is ALWAYS running as soon as I turn the car on if that helps. Any further input?

Jay

Just to consider the idea that the catalytic converter installed here is bad.. If I were to remove the converter from the exhaust line and just replace it with a pipe, if this were the problem, then the overheating should go away right? The converter here is bolted on so would be easy to pull from the exhaust line.

Jay

Sure. I also read your reply about just recently having a new cat installed, so now I cant say what the issue might be.

The stumbling/overheating didnt start after the new cat was installed, did it?

Well.... You 'could' be describing a bottom end bearing that is about to blow up....

How is the oil pressure?

Do you get any knocks when it's first started cold?

Mike

Ford Warrior wrote:

I'm going to have to call up the shop/lot I bought it from last week and see if I can get any truthful answers out of them. Theyll probably just push me aside though as the car was sold "as-is" with no warranty unfortunately

Jay

Mike

I don't get any knocks - the vehicle starts right up and performance seems flawless aside from what I've outlined in my posting. The dashboard fluid indicator gauge is always near the upper end. The oil dipstick always indicates where it should be if not a little high. How would I check the oil pressure?

thanks Jay

You would need to either buy a mechanical gauge or have a garage put a test gauge in to see what it is at idle and at speed. If a main bearing is bad, the oil pressure will usually be low.

When you just turn the key to 'run', not start, does the engine or oil light on the dash come on? It should so you know it is working. If the pressure was really low, some oil lights will flicker at hot idle, but a real gauge is the only way to check for sure. If it doesn't come on for the test, then you should address that first.

Mike

Start with simple stuff first.

maybe the rumbling is the fan clutch slipping.

my 2 cent's you have a cooling problem van clutch? water pump on its way out ? stuck thermostat? radiator glogged ? crap in front of the radiator ?

as for the hum bad wheel bearing will make your car hume at certain speeds ?

mybe they put in a new tranny and its out of balance tourqe convertot to flex plate ?

But he hasn't got a van.

I think he locked the door already.

Glogged or glugged? Plogged or plugged?

The dog has been put down and the cat craps in the flower bed, so...

Hume or hum? Hume is a philosopher. Hum is something you do when you don't know the words. This happens at any speed.

Or maybe the tourniquet came loose and the heroin leaked out of the convertot.

Tudy, (may I call you Tudy?) you really, really need to learn how to spell and type.

Spelling errors aside, this post is pretty close to what I was thinking - that the noise and the overheating are not related to each other. Rev up your motor in park. I bet you do not get the noise. Bad wheel bearings, axles, tires, or transmission problems could be the culprit.

While revving at idle, if it starts overheating (and the fan is running) you almost certainly have a clogged radiator, heater core, partially stuck thermostat, lack of cooling system pressure, or something else impeding either the flow of coolant or the removal of heat from the coolant. Barring all of that, too far advanced timing will make it run hot, but usually not hot enough to overheat.

An update is in order here... The lot/shop I bought the van from claimed they were "sure" it was a bad thermostat.. so they took some more of my $$ to replace the thermostat and now the problem seems even worse. Now it seems to run at normal speeds slightly hotter and STILL overheats on the highway at speeds over 55mph. I just went to autozone and purchased a new fan clutch but haven't installed it yet as I'm not even sure this is the proper next step. It seems to me the speeds at which I'm driving on the highway should be enough to cool the engine to some degree just as much as the fan clutch would be doing.. or am i thinking wrong here? I'm just thinking that if it were the fan clutch that were out of order then perhaps the overheating would be happening while idling. The shop claims the radiator is not clogged at all and is circulating and the water pump appears to be fine. Does anyone have any further input before I blow $40 by trying to install this new fan clutch which may or may not fix the problem?

Thank again for your help Jay

You don't need a cooling fan at all when you're driving 55 mph, which proves that your overheating problem isn't caused by a defective fan clutch. Note that doesn't mean you don't have a defective fan clutch, but you definitely have another problem causing the overheating.

No, you are correct there. The fan is generally just to keep air circulating when you are stopped. When you are driving forward, air is pummeling the area that the fan would be cooling.

That leaves the heater core or a pressure leak, assuming the shop has done their job properly. You can double check them by allowing it to idle and then pinching the upper radiator hose - you should be able to feel the pressure behind it once the thermostat has opened, and it should increase proportionally with engine RPM.

If your radiator is full, a pressure leak should vacate coolant at that spot (leaky hose, gasket, freeze plug, hole in radiator, etc) so I'm assuming you do not have this.

If you suspect your heater core of all things, get a pipe fitting and simply bypass it (one heater hose into the other instead of into the firewall) and see what happens.

A really long shot here would be a potential head gasket leaking exhaust into the coolant. That tends to cause mysterious cooling problems. You can check this by looking for bubbles under the radiator cap as you warm it up. There should be few to no bubbles.

Just to check this angle.. As I said before I can feel a deep rumbling in the van as I drive from 55 to 65mph and it also feels like there is a large amount of tension/pull in the drivetrain at this speed. I let off the gas at this speed and it seems like the speed decreases abnormally fast like it's being pulled back. Could the overheating at this speed be connected? Perhaps the engine is overworking due to some transmission problem or friction in the drivetrain somewhere? .. I'm just trying to figure out what my most economical and straight to the problem option would be here.

Thanks again Jay