Nefario

Long story... last fall we bought a 1997 Civic that had been driven by a college girl and kept running by her dad. Everything looks 99% original.

- Christmas 2016, my son comes home with no water visible in radiator top or overflow. Bad radiator cap made essentially an open system. Replaced with generic cap.
- February blew heater hose under distributor, cut end off and re-clamped.
- March blew top radiator hose, replaced
- March discovered wrong top radiator hose ID, was leaking at spring clamp, replaced with correct hose and band clamp
- May discovered water blowing out around generic radiator cap, made gasket, didn't help.
- June replaced radiator, new cap, main hoses, & thermostat
- June blew heater hose under distributor again, replaced with new.
- July saw leaks under water pump area. Mechanic replaced water pump and timing belt.
- July replaced sparkplugs and wires, they all looked pretty much equal.
- No leaks for 2 weeks driving ~30 miles/day
- July, today, blew U-shaped bypass hose. It had felt soft and I was thinking of replacing it....

The car runs generally OK and temp gauge stops at midrange ~horizontal
- Have not checked compression
- Have not checked for exhaust gases in radiator
- It's had at least two chances to be seriously overheated but my son says he's never seen any warning lights.

Are these this just 20-year-old hoses giving out when subjected to the new normal pressure?
Should the radiator cap be able relieve pressure of a small head gasket leak or would a hose blow first?

What to do next after replacing the bypass hose?

fragmare

This all sounds like a car that has been left sitting for a long time (year+). If you REALLY want to put your mind at ease about a head gasket, you can just go to any parts store and buy/borrow one of those turkey baster looking Combustion Leak Detector kits and use the blue fluid that comes with it. While the coolant is bleeding is a perfect time to use it too. Really, though, it just sounds like a bunch of rotten hoses, clamps, o-rings, etc.

StayKrafty

Is the overflow topped off to the max line? Does coolant blow into the overflow and then back to the radiator. When the car is cool, take the radiator cap off, and start the car, does it gush coolant out?

Nefario

Before the water pump replacement I could top off the overflow tank and it would lose about 1 cup of water in 40-50 miles from sucking it back into the engine when it cooled off.

With the new radiator and everything sealed the water pump leak happened quickly and left a puddle under the car. With the new water pump the overflow tank maintained its level for about two weeks until the latest heater hose blowout. When cold and running the water does NOT gush out nor do I see any bubbles in the radiator or overflow.

The Honda seems to work on higher pressures than I'm used to and I've never seen any bubbles rising in the overflow tank as the engine warms up. I'm now down to only one original hose between the heater valve and heater core. Maybe it's fixed?

I appreciate the responses! I needed a reality check - this is our first Honda - I'm generally impressed...

mk378

Get radiator completely full. Start engine cold with the radiator cap off and rev it. If bubbles / coolant gush out, bad head gasket.

The radiator cap controls pressure in the system. It also depends on the hose from the radiator to the reservoir being unobstructed.

Mr.Waffles

Not to restart an old thread. Similar issue. Coolant is pushed into the overflow slowly drive by drive until it flows over into the battery tray. Replaced the radiator cap. Small leak found at the upper hose and lower heater hose. Would this cause coolant to not be taken back up? Woukd two small leaks cause a system not to turn to vaccum and being the coolant out of the rez. Am i just lookokg at a blown HG?