1998 Dodge Neon engine overheats

PRANKSM26

MEMBER
1998 DODGE NEON
4 CYL
2WD
AUTOMATIC
138,000 MILES

Hi,
i have a 1998 dodge neon, two days ago it started, idling roughly but was fine at higher speeds, I also experienced loss of brake pressure at low speed (2-5 mph) and the engine was heating up excessively at high speeds 70-80 mph, the fans were working fine, so I had to pull the car to the shoulder & I even tried to turn the heat on in the car (parked car, engine not running) as I had heard that it helps the engine cool down, but that resulted in the temprature gauge going up instead of down. I showed it to a mechanic & he said that I need new plug & the radiater needs to be flushed. However later I discovered that the vacuum lhose going from the EGR vaulve, to the engine was broken in the middle, after replcing it the idling & braking have come back to normal, my question is whether the broken vacuum hose could have caused the engine to heat up? Or do I still need to get the radiator work done.

3 Replies

CARADIODOC

MECHANIC
33,871 POSTS

The overheating sounds more typical of a leaking head gasket. You are correct about using the heater to help cool the engine. I'm not sure why that didn't help.

The test that should be performed checks for combustion (exhaust) gases sneaking into the cooling system. I call it the "sniffer" test. It involves drawing air from the radiator neck through a glass tube with two chambers partially filled with a special dark blue liquid. If combustion gases are present, the fluid will turn bright yellow. That is near positive proof of a leaking head gasket. The radiator could be partially plugged, but any overheating that would cause usually shows up over a long period of time, not all of a sudden unless you have an unusually hot day.

Caradiodoc

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Tuesday, April 6th, 2010 AT 7:28 PM

PRANKSM26

MEMBER
2 POSTS

But could the broken vacuum hose have lead to the overheating, as I read somewhere that a nonworking EGR vaulve can cause Excessive exhaust backpressure

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Tuesday, April 6th, 2010 AT 7:39 PM

CARADIODOC

MECHANIC
33,871 POSTS

These two things should be two separate issues. With the broken hose to the EGR valve, the valve simply wouldn't open when it was supposed to. The EGR valve will not open at idle or low speeds anyway. It will only open at highway speeds to send a little exhaust gas into the cylinders to displace some of the incoming air. Whether the system is working or not, it should not cause engine overheating.

Without the inert EGR gas entering the engine there will be a little more air and fuel. That might result in a little more heat being developed, but that would be no different than driving 5 mph faster. The cooling system is more than capable of handling that extra heat.

Caradiodoc

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Tuesday, April 6th, 2010 AT 10:57 PM