Malfunctioning EGR cause car to run really hot?

DaveB · May 21, 2004

My car has a problem with running hot (especially since its getting hotter now) but it never actually overheats. What happens is it gets to the A or so in NORMAL, even on the highway. However, when the car idles, it never overheats, or gets above the R in normal. So Im thinking it may be the EGR thats causing it, since I just read that the EGR doesnt function when the engine is idling. Now for those of you with the kit, did your car run cooler when the EGR was eliminated? This problem started after I did my headers/x-pipe/smog eliminator/plugs and wires. Now I had to take the EGR off to get the header on the pass. side in, so I think that might be the culprit, since I didn't touch anything else that could have effected the engine temps. Thanks.

And yes, my fans work fine.

Mrgreen94gt · May 21, 2004

The cooling system may need burping, the t-stat may be malfunctioning, or the water pump may be going out. Mine started getting really hot back in Sept, right before the radiator decided to burst at the seams.

My EGR quit working years ago, and I never noticed a change in temp. The intake doesn't seem to heat up quite as much with the EGR disabled.

The Hitman · May 21, 2004

Agreed. My EGR is currently down and I've noticed no increase in temp whatsoever.

BlackVert · May 21, 2004

the egr is actually designed to keep the engine from getting too hot by "diluting" the mixture with some co2. if you take it off, it follows that you would run hotter.

DaveB · May 21, 2004

Mrgreen94gt said:
The cooling system may need burping, the t-stat may be malfunctioning, or the water pump may be going out. Mine started getting really hot back in Sept, right before the radiator decided to burst at the seams.

My EGR quit working years ago, and I never noticed a change in temp. The intake doesn't seem to heat up quite as much with the EGR disabled.

Well the thing is, this problem started happening out of nowhere after a round of mods last summer. Last summer I put on BBK LTs, a Dr. Gas offroad X, an ASP smog pump eliminator, new plugs and wires, and even put in a bottle of Water Wetter.

After that my car ran hot as hell, even on the highway. Im talking between the A and L in normal with the cruise set at 70 (2000 rpm with my 3.08s), and the rpms never going 2500 the entire trip. Now I had to take the EGR off to put the headers on, and had to shorten the EGR tube to make it fit, now Im thinking it might be the EGR thats causing the problem, maybe being stuck all the way open or something, since the problem isnt there at idle, and the EGR doesnt function at idle, and it doesnt get super-hot when idling, even then sitting there for a long time. After the problem started, I had the cooling system completely flushed and had a new thermostat put in, but still no real improvement. But the problem is still there, especially on the highway. I did a search and someone said after they got an EGR delete plate, their car ran a lot cooler. I have a feeling if I put in a Fluidyne (which I plan on getting soon) the problem would be better, but still be there. Thanks for the replies, keep them coming

DaveB · May 21, 2004

Black96VertGT said:
the egr is actually designed to keep the engine from getting too hot by "diluting" the mixture with some co2. if you take it off, it follows that you would run hotter.

Im thinking its just pulling in too much hot exhaust air, the upper intake feels like you could cool eggs on it after a little a little while.

Also, the car gets hot pretty quick, even keeping the rpms to 2500 just driving around.

DaveB · May 22, 2004

The Hitman · May 22, 2004

If the EGR was stuck all the way open you would probably notice driveability problems.. Exhaust can't be burnt twice..
If the EGR were all the way closed.. I could see you getting a problem with overheating (possibly becuase that's not the case with me) because it actually COOLS the combustion temps when it's working properly. If your not getting any then the combustion temps go up.
However.. if either of these were the case you would probably get a CE light because the position sensor would pick up that it was either all the way open or all the way closed and not moving.

DaveB · May 22, 2004

Any other ideas as to what it could be? What really baffles me is that the car will act fine while idling, but when on the highway @ 70 mph the temp guage is between the A and the L. My friend said that it could maybe be my sparkplugs? I'm pretty sure I got Autolight 25s, I cant remember the number exactly, but it was basically a stock replacement.

Mrgreen94gt · May 22, 2004

Try changing the plugs to Autolite 24's. They solved a similar problem that I was having about a year or so ago. There is a possibility that between the no EGR and the new exhaust, that you might have hotter combustion temps. The colder range plug should take care of it.

It seems like our stock plugs aren't as ideal once the power starts going up a little.

DaveB · May 23, 2004

Mrgreen94gt said:
Try changing the plugs to Autolite 24's. They solved a similar problem that I was having about a year or so ago. There is a possibility that between the no EGR and the new exhaust, that you might have hotter combustion temps. The colder range plug should take care of it.

It seems like our stock plugs aren't as ideal once the power starts going up a little.

Are they one heat range colder than stock? You really think just adding headers and an x-pipe could do that? Well I just checked my old receipt and sure enough I do have the 25s with . 054 gap. You think the 24s will solve this problem?

Mrgreen94gt · May 23, 2004

DaveB said:
Are they one heat range colder than stock? You really think just adding headers and an x-pipe could do that? Well I just checked my old receipt and sure enough I do have the 25s with . 054 gap. You think the 24s will solve this problem?

It cleared up my temperature issue and a pinging issue that I was having, however, my plugs were fouled pretty badly due to oil being sucked through the intake. It couldn't hurt anything to try them, since it has seemed to work for quite a few people on here. Just one heat range seems to be pretty effective.

I guess an exhaust change could cause something like that, probably more likely with longtubes.

DaveB · May 23, 2004

Alright well I went by my local parts store but they were closed today , so I guess Ill head over there tomorrow morning and hope for the best. Thanks a lot .

EDIT-would the colder heat range hurt performance at all? Because when then engine is actually at a cooler temp, it runs pretty good.

Mrgreen94gt · May 23, 2004

DaveB said:
Alright well I went by my local parts store but they were closed today , so I guess Ill head over there tomorrow morning and hope for the best. Thanks a lot .

EDIT-would the colder heat range hurt performance at all? Because when then engine is actually at a cooler temp, it runs pretty good.

Try Wal-mart, that's where I get mine. I couldn't imagine it hurting performance, mine seems to run better for a longer time with them.

DaveB · May 23, 2004

Alright I know where Ill be heading after dinner. Also FWIW, I let my car idle in the driveway for 20 minutes today, and the temp guage was only between the O and R, so it only really seems to heat up when the car is under a load.

DaveB · May 25, 2004

Well I swapped in the 24s, today, and while they seemed to help, they only seemed to slow the process down. On the highway the temp guage was still in the A . I will admit though, that today was very hot, so Im sure that didnt help. Cruising around town, it seemed like it just slowed the amount of time it took to get hot down, like it took almost double the time. Any other ideas?

Mrgreen94gt · May 25, 2004

Well, at least it slowed the process down. That leads me to thinking that there is already a weak link in the cooling system that the disabling of the EGR may have exaggerated. It almost seems that 10 years is the lifespan of our cooling system components, it seems like mine have been going out one by one over the last year.

What degree thermostat do you have now?

Also, a lot of our cars' cooling issues are related to how late the fans come on mixed with the inefficiency of the stock radiator.

DaveB · May 25, 2004

Im almost postitive I have a stock replacement in there. Also, I havent eliminated the EGR...yet, may try that to see if it helps.

It sucks first driving around I thought it had worked, but sure enough the temp guage crept up there . Well I have a Fluidyne planned for the summer anyway, hopefully that will totally get rid of the problem. Thanks for the help, I really appreciate it.

Malfunctioning EGR cause car to run really hot?

DaveB

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