A finite-difference model was used to investigate the unsteady heat transfer in a combustion-chamber deposit. Experimental surface temperature measurements were used as boundary conditions for the computational study. The temperature dependence of the deposit conductivity was modeled using a power law relationship, k = A · TB. The numerical value of the exponent, B, was estimated from data available in the literature, and the value of A was then determined from the experimental data.Both the amplitude and the time lag of the temperature fluctuations at the deposit-wall interface were investigated and used to estimate a value of deposit heat capacity, ρC. Both the instantaneous heat flux at the deposit surface, and the total heat loss were investigated.