1988 V-4 1.6L Crossflow Overheating

[Solittle]

I am trying to get this engine back in service after no use in a year and a half. I put in a new set of plugs, new water pump and gear oil. It starts fine in the driveway and runs a temp of 135-140 degrees as measured by a temp gun.

I took it for a test run this morning and again it started fine in the water and ran around 135-140 degrees for a half hour or so. I opened it up after leaving the channel and initially it seemed to run fine . I went to WOT (5,400 rpm)and ran for 5 minutes or so before the temp horn went off. I pulled the hood and the temp on one bank was around 196 with the other just over 200. I limped back to the ramp on my other engine.

My only thoughts are that there is some kind of restriction that is preventing the full water flow when the engine is working hard. This is a 20 year old salt water engine but it has been rebuilt and flushed after every use.

Any thoughts?

 

[kenmyfam]

Re: 1988 V-4 1.6L Crossflow Overheating

Are the stats functional ??? have you tested them ???
Test them in a jug of water and a meat thermometer. Should open around 140 degrees.

 

[Solittle]

Re: 1988 V-4 1.6L Crossflow Overheating

Are the stats functional ??? have you tested them ???
Test them in a jug of water and a meat thermometer. Should open around 140 degrees.

The stats are open as I have run this engine at low rpm for an extended period of time. It overheated only when I put it to WOT.

 

[ob]

Re: 1988 V-4 1.6L Crossflow Overheating

Insure you have good flow from your relief ports at high speed.Did you replace all of the T/stat components or just the vernatherm?

 

[emdsapmgr]

Re: 1988 V-4 1.6L Crossflow Overheating

The thermostats provide cooling water at idle. When on plane, the pressure relief valves open, flooding the block with extra water. If these valves ever get distorted from overheat, they may not be functioning properly at higher rpm's. If you pull the thermostat apart and find them in good condtion, you may want to check for water restrictions under the head covers or in the block.

 

[kenmyfam]

Re: 1988 V-4 1.6L Crossflow Overheating

Just has to be a restriction somewhere. And not much of one seeing that it will only sound the alarm at WOT