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Is it safe to drive 600 miles in a day with CEL on?

I drive a 97 Camry, and there’s a known issue with the head gasket leaking, but my mechanic sealed it with silicon. I’m trying to visit someone, and I’m worried about my car making it there and back. Other than the sealed leak, there’s nothing else wrong with the car, and it just had an oil change today.

If there is nothing else wrong with the car, then why is the CEL lit up? :worried:

That CEL could indicate something serious enough to leave you stranded only part-way through your trip, or it could indicate something that could wait until you return from your trip. Nobody from afar could possibly know the reason(s) for the CEL to be lit up, and unless you have the stored trouble code(s) “read” you will not know either.

If you go to an auto parts store (Auto Zone, O’Reilly, Advance Auto), they will “read” the code(s) for you, and then you can return to this thread in order to post them and get some opinions on just how serious an issue they present.

Personally, I wouldn’t drive more than few miles without knowing just how serious those trouble codes actually are, but you may have a much higher risk tolerance than I do.

And, speaking of risk tolerance…are you SURE that your mechanic “sealed” your head gasket with silicone?
My best guess is that he may have sealed a leaky valve cover gasket with silicone, rather than a head gasket.
The combustion pressures that a head gasket has to withstand makes it unlikely that silicone would actually “seal” a leaky head gasket for very long.

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Agree with @VDCdriver! The CEL has a purpose; to tell you when it detects some sort of problem. It could be a minor problem or it could be a major one. There is no way we we can tell major from minor just knowing the light is glowing. You need to get the codes read from the car and post them here. It will be in the form of “P0XXX” or may even be “CXXXX”.

A truck I own decided to set the CEL right before a 2200 mile round trip. The codes told me the “heater” for one of my oxygen sensors had failed. I knew this to be a “nothing” kind of failure not affecting fuel economy or engine operation. It was a minor emissions issue, so I took the trip anyway and replaced it when I got to my destination.

Post back with the codes and we will help.

I also noticed the “sealed it with silicone” comments and wondered if it wasn’t the valvecover gasket that was bad. One cannot seal a breeched headgasket with silicone. It would only survive the heat and pressures from the combustion chamber for a nanosecond… and pulling a head and using silicone to fix a headgasket breech, well, it makes no sense.

Is it safe to drive 600 miles with the CEL light on?
Well, it won’t kill ya. But you’d better have the train schedule handy if you expect to complete the trip. And you’d better have a replacement car selected before you leave. Driving 600 miles with the CEL on just might end up in a permanently damaged engine.

One can seal a head gasket leak with sodium silicate.

I believe that’s what the OP was referring to.


Get the CEL read for free at any chain auto parts store and see what the code says. Odds are this is the least of your concerns unless the CEL is FLASHING. If FLASHING, then DO NOT drive the car at all until it is fixed. Yes, the severity of the problem could range from minor to moderate and no one will know without more information.

If the valve cover gasket (leaking oil) was sealed with sealant, then this is an acceptable repair. If the head gasket was sealed with sodium silicate, then you are gambling. I hear stories about this repair working quite well for certain people. I also hear stories about it not working or even causing other problems. I wouldn’t really want to drive this car very far if the head gasket was repaired with this questionable substance. Remember this is what they used to lock up engines in the cash for clunkers era.

IF you go, buy a couple jugs of universal premix coolant just in case to limp to the next town. Don’t open them and simply return them when you get home. I have been known to purchase extra car parts before a long trip and keep them in the package, only to return them unused when I get home.

One of my friends had lost his job a few years back and was hurting for money. He sold his car and only kept one around for the wife to drive. He got a job and a family member gave him a rusted out old beater with a questionable transmission and blown head gasket. The car was junk but he poured a can of the silicate sealer in the radiator and drove it for several months until he had some money saved up for a newer car. His work was only a couple miles away and by the time he was ready for a new car, the sealant had started to give way once again. Use of this product isn’t a bad idea for a junk car like this just to prolong it a little while longer. I would NEVER suggest using it on a car that actually was still worth something and would be worth repairing the CORRECT way for several more years of reliable service.

Interestting, Tester. I’d never heard of using sodium silicate for sealing headgaskets… only for totally and permanently destroying engines for Cash4Clunkers. It’d be interesting to hear from the OP as to whether that’s what he’s alluding to. OP?

The CEL can come on b/c the fuel tank cap is a little loose. That’s not going to prevent your trip from happening. But it can come on b/c the ignition system is about to go kaput. That one will delay your arrival, or worse. As others have already posted, it depends on why the CEL is on. In any event, with a known head-gasket problem, make sure to monitor the engine coolant temp gauge, and if it starts to heat up beyond normal range, immediately turn off the AC and turn on the passenger compartment heater to max. If it continues to heat up, you’ll have to pull over and wait for a tow truck. I think you’ll probably make it though, provided the CEL is on now for some innocuous.

Sodium silicate has also been used to repair radiator leaks.

I believe you, but I’d rather trust more traditional methods… like replacing the radiator!

I have no argument with that. You asked what sodium silicate might be used for and I provided an answer. It’s only meant as a stop gap until a real repair, like replacement, can be made.